These
are
stories
from the
last few weeks...
January 31, 2012: Winter Birds
Would you believe that we Americans
spend more than $3 billion each
year on bird food, plus another $800 million on bird feeders,
birdbaths, birdhouses and other bird feeding accessories? These
statistics from the U.S. Fish and Wildlife Service also tell us that
one fifth of adult Americans are self-identified as birdwatchers. What
is it about these seemingly fragile creatures that catches our interest
and causes us to open our pocketbooks to such an extent?
Birds are feathered, winged,
two-footed, warm-blooded, egg-laying,
vertebrate animals and there are around 10,000 living species that
inhabit almost every corner of the planet. In size, they range from the
2-inch bee hummingbird to the 9-foot ostrich. In spite of these rather
unique characteristics, most of us have half a dozen types visiting our
yards every day and birds are so numerous that many people scarcely
notice their presence.
These interesting creatures have a
much higher metabolism, and thus
higher body temperature, than humans. While the exact measurement
varies for different bird species, the average body temperature is 105
degrees F. and it can be a challenge for a bird to maintain such a high
body heat when temperatures dip in northern climates. Smaller ones are
particularly at risk, since they have a proportionally larger surface
area on their bodies to lose heat but a smaller core volume to generate
it. (It is interesting to note individuals of the same species living
in colder regions tend to be larger than those living in warmer areas.)
Birds will shiver to raise their metabolic rate and generate more body
heat as a short-term solution to extreme cold. While shivering does
require more calories, it is an effective way to stay warm.
Cold temperatures are survivable by
most birds as long as they have a
sufficient supply of nourishment. Some birds prepare for the winter
months by collecting food in the summer and fall months and hiding it
up off the ground for later use. Some eat dormant insects they find in
the crevices of tree bark while others feed on standing weed seeds and
any remaining berries such as serviceberry and juniper. Even small
birds can build up fat reserves to serve as insulation and extra energy
for generating body heat, and many birds will gorge during the fall
when food sources are abundant, giving them an extra fatty layer before
winter arrives.
Birds usually wait out the coldest
periods protected from the wind in
evergreen or shrub thickets. Some species huddle together in artificial
or natural cavities, sometimes even stacking on top of each other to
keep warm. Feathers provide remarkable insulation against the cold, and
many bird species grow extras as part of a late fall molt to give them
thicker protection. The outer contour feathers lie on top of each other
much like shingles on a roof, and tend to shed rain, keeping the body
dry and well insulated. Down feathers make up the inner layer and lack
vanes and barbule hooks, creating a fluffy tangle of insulating air
pockets. Semiplumes are a cross between contour feathers and down, and
provide an additional layer of warmth that can keep insulating air at
nearly 70º. Birds will fluff out their feathers for additional
insulation in the coldest temperatures.
Most birds have a "preen gland" which
is located near the base of the
tail and secretes a useful oil that helps keep the feathers flexible
and waterproof while inhibiting the growth of fungi and bacteria. The
bird uses its beak to squeeze oil from the gland and apply it to its
feathers, and then spreads the oil onto its head with its feet.
Birds’ seemingly bare legs and feet
are covered with specialized scales
that are composed of the same keratin as beaks and claws, and are
thought to have much the same structure as those of reptiles. These
scales are not living tissue and are thus less susceptible to freezing
while minimizing heat loss. Beneath the scales are fine webs of blood
veins that are warmed by arterial blood flowing in vessels situated
close by. In addition, birds have no sweat glands so heat and vapor are
transferred to the lungs and eliminated through the mouth, a process
that prevents any moisture from their skin or feet freezing them onto
perches.
A few birds, such as chickadees, can
enter torpor to conserve energy
during the coldest winter nights. Torpor is a state of reduced
metabolism when the body temperature is lowered, therefore requiring
fewer calories to maintain the proper heat. Most birds can lower their
body temperature by a few degrees, but torpid birds have lowered their
body temperatures by as much as 15 degrees F.
There is some controversy about the
wisdom of feeding birds, as
problems can arise if equipment is not kept clean and birds in close
contact may spread disease; still, studies have proved that the
additional food allows many more songbirds to survive, particularly in
very cold and snowy winters. Bill and I will continue to feed them and
enjoy their visits, as the year-round pleasure that they provide more
than repays us for any effort.
--------------------------------------
January 24, 2012: Red-tailed Hawks
The male red-tailed hawk perched on the glove of its handler, its right
wing held at what looked like an impossible angle. Its attention was
fixed on the man’s other hand as it dipped into his waist pack bringing
out a scrap of meat, and the bird grabbed it with its sharp beak and
gobbled it up. The hawk was one of four raptors on display at the
program presented at the Sauk Eagle Watching Days, and seeing these
magnificent birds up close was the highlight of the day.
While the eagle was truly the star of the show, it was the red-tail
that most interested me. Members of this species nest in the woods
across the field from our house, soar overhead daily as they survey
their territory, and hunt in our fields. It is probably the most common
hawk in North America and is one of three species often called
"chicken-hawk," (along with Cooper’s and sharp-shinned) though it
rarely preys on adult chickens. Just last week we watched a pair
sitting only a foot or two apart in one of the oaks across the field,
probably keeping out a keen eye for a meal.
Though their backs may be light or dark, the basic appearance of these
hawks is the same. It is the breast that usually catches the eye when
the bird is perched, as its light brown feathers stand out almost white
against any background. There is often a dark brown band across the
belly, formed by horizontal streaks in patterning, and, of course, the
brick-red tail, which gives this species its name. In flight one can
see a short, broad tail and thick, chunky wings, and if one is close
enough to see detail, the short dark hooked bill, and the yellow cere
(the fleshy covering at the top of the beak), legs, and feet. The male
may weigh from 1.5 to 3 pounds and measure 18 to 22 inches, while a
female is often 25% larger and can have a wingspan of more than four
feet.
Perhaps you have heard the cry of one of these birds as it flies
overhead. It is a two to three-second hoarse, rasping scream, described
as kree-eee-ar, which begins at a high pitch and slurs downward. It is
an interesting fact that some Hollywood directors seem to think this
cry is typical of all raptors, because no matter what species of hawk
or eagle appears on screen, the shrill cry on the soundtrack is almost
always that of a red-tailed hawk.
Red-tails reach sexual maturity at two years of age and choose mates
for life, (unless accident or illness causes one to die) and they tend
to remain in the same nesting territory. During courtship, the male and
female fly in wide circles while uttering shrill cries and the male
performs aerial displays, diving steeply, and then climbing again. They
will refurbish a nest used in a previous year if possible, but
otherwise build a new one -- often only a few hundred yards from the
previous site. The nest itself is usually a tall pile of dry sticks
that can be up to 6 feet high and 3 feet across, with an inner cup
lined with bark strips, fresh foliage, and dry vegetation. The female
lays a clutch of 1 to 3 eggs in March or April, and incubates them for
28 to 35 days. The chicks remain in the nest for about six weeks, and
then are fed and taught to hunt by the parents throughout the rest of
the summer.
The red-tailed hawk hunts primarily from an elevated perch, swooping
down to seize prey when it appears. Its diet is mainly made up of small
mammals such as mice, squirrels, and rabbits, but it will take insects,
birds and reptiles when it can find them. Because the red-tails are so
common and easily trained as capable hunters, they make up the majority
of hawks captured for falconry in the United States. Falconers are
permitted to take only young birds less than a year old that have left
the nest and are on their own, so as to not affect the breeding
population. Since there are fewer than 5,000 falconers in the United
States, any effect on the million-plus red-tailed hawk population is
thought to be insignificant.
In the course of a hunt, a falconer most commonly releases the hawk and
allows it to perch in a tree or other high vantage point. He then
attempts to flush prey by stirring up ground cover, often aided by a
dog. A well-trained red-tail will follow the falconer and dog, knowing
that they will provide opportunities to catch game. Once a raptor makes
a kill, it does not bring it back to the falconer. Instead, the
falconer must follow the hawk to its captured prey, carefully approach
and trade the bird a piece of favorite meat in exchange for its prize.
The feathers and other parts of the red-tailed hawk are considered
sacred to many American indigenous people and, like the feathers of the
bald and golden eagles, are sometimes used in religious ceremonies and
found adorning the their regalia. As with the other two species, the
feathers and parts are regulated by the eagle feather law, which
governs the possession of feathers and parts of migratory birds, but
Native Americans are allowed exemptions.
The wing of the red-tail we saw at Eagle Days had been injured by
collision with a vehicle and since the bird was no longer able to hunt,
it has been kept for demonstrations by the St. Paul, Minnesota Raptor
Center along with others incapacitated by poison or accident. The
Center treats some 700 raptors each year, releasing those that can
return to the wild, finding homes for survivors that cannot, and
providing training in avian medicine and surgery for veterinarians from
around the world.
------------------------------------
January 17, 2012: A New Invader
If you are a gardener or farmer, I may
have some bad news. We have
fairly well survived the onslaught of houseflies, Japanese beetles,
gypsy moths, elm beetles, and most recently, Asian ladybugs and Emerald
ash borers, but the worst alien bug may be yet to come...
Every child who has played in the dirt
knows the stinkbug, an insect
that gives off a distinctive smell when squashed or even annoyed. It is
large as such beetles go, about ¾ inch in length, and has a
distinctive “shield” shape. Stinkbugs have glands which produce a foul
smelling liquid which is a defense mechanism meant to prevent it from
being eaten by birds. They also have sharp sucking mouthparts that are
capable of damaging fruit and vegetables, but are seldom found in
numbers large enough to cause much concern.
All that has changed, however, as the
brown marmorated stinkbug, native
to China and the Far East, has arrived. It was first noticed in
Allentown, Pennsylvania in 1998, and has spread across that state,
wreaking havoc as its numbers increased. In 2000, one was recovered in
New Jersey from a black light trap, and from there the insects moved
into Delaware, Connecticut and New York. By 2009, this agricultural
pest had reached Maryland, Virginia, Tennessee, Ohio, and Oregon, and
as of November 2011, it has been see in 34 states including Illinois,
Minnesota, and Wisconsin.
The brown marmorated stinkbug
(‘marmorated’ refers to its marbled or
streaked appearance) begins feeding in the spring on a wide range of
fruits, vegetables, and other host plants. The bug pierces leaves and
fruit using its sharp proboscis and sucks out juices while injecting
saliva, causing disfigurement and rot. This resulted in an estimated
$37 million in apple agricultural losses alone in 2010 in the
Mid-Atlantic region, and one extension agent in Pennsylvania reported
that he had seen orchards with 70% of the fruit injured. "It's another
introduced pest that we have to learn to live with as time goes on," he
bemoaned. "We have to learn how to manage it. For now we're learning by
trial and error."
In addition to the crop damage, the
stinkbugs survive the winter as
adults by entering houses and other structures. When one finds a site
that is suitable, it releases a chemical that attracts others to the
area. There they hibernate until the warmth inside the building causes
them to become active, and they may fly clumsily around light fixtures
by the dozens, sounding like aggravating little helicopters and
emitting their vile smell when threatened. Allegheny County
Pennsylvania entomologist, Bill Todaro, has been getting daily calls
from distraught county residents, but tells them, "Stink bugs...are
proven tough bugs but at least they don't bite, sting or do damage to
the house. There are worse things out there." In response, Nancy
DeMuro, of Jefferson Hills, PA, said in a desperate-sounding email,
“They fly around and buzz when they're active and then land in our
lights or on our robes or on our beds...UUUGGGHHHHH!"
Adults emerge from hiding in May to
mate and deposit 20 to 30 tiny
yellow eggs on the underside of leaves. These hatch into small black
and red nymphs that go through five molts and are similar to adults
without wings. Fortunately, there seems to be but one generation a year
in this country, in contrast to Asia where they manage four in a
growing season.
Lacking natural controls here,
stinkbugs are multiplying explosively.
They seem likely to cover the country, unless disease or a natural
predator emerges to bring their numbers to balance. In China, a small
wasp that is not currently present in the U.S. is a primary predator
and it is undergoing study for possible introduction in this country,
as well as several other species of the parasitoid wasps that have been
observed attacking stinkbug eggs. Some species of spiders and praying
mantises will attack adult stinkbugs but at this point, no natural
controls seem effective.
The stinkbugs are not known to cause
harm to humans, although residents
become upset when the bugs enter their homes and noisily fly about.
They cannot be squashed or vacuumed up, as the resulting smell can be
quite disagreeable. On the other hand, Andrew Strube, an unemployed
entrepreneur, has found the stinkbug to be a godsend. He devised the
Strube Stink Bug Trap which consists of a bug-luring light enclosed in
a cylinder covered with sticky stuff and has sold 1000s on the internet
and in hardware stores.
Meanwhile, the U.S. Department of
Agriculture and Penn State
researchers, among others, are working on methods to lure and kill the
bugs or perhaps repel them. Unfortunately, it’s not so easy, as
exterminators report that common pesticides don’t often work. Everyone
agrees, however, that in the home, prevention is the key and residents
are instructed to seal all possible openings to the outside. The
experts also suggest that outdoor lighting be kept to a minimum, since
the bugs are attracted to both the brightness and the warmth. In fact,
the same instructions that were given with the invasion of the Asian
ladybugs seem to be repeated here. It may be an interesting summer if
they make it to our area.
--------------------------------
January 10, 2012: Jack Frost
Among winter's beauties are the intricate crystals that sometimes form
on roadside weeds, shrubs, branches, wires and other objects on clear
frosty nights. These are known as hoar frost and may sometimes be so
thick that they look like snow. The name ‘hoar’ comes from Old English
and refers to signs of old age, relating it to the frost which
resembles elderly white hair on trees and bushes. The development of
hoarfrost is somewhat similar to the disposition of dew in the summer
and both accumulate on objects when there is more moisture in the air
than it can carry.
The temperature at which the air is totally saturated (the humidity
reaches 100%) is called the dew point. If the temperature of humid air
is lowered below the dew point, the air must lose part of its suspended
water through rainfall, snowfall or the formation of dew or hoarfrost.
If the dew point is above freezing, then dew forms, but if the dew
point is below 32°F, then hoarfrost occurs.
Hoarfrost consists of crystalline structures that appear in an
intricate variety of forms -- needles, platelets, ferns and feathers,
depending upon the surface and the temperature at which they developed.
Frost crystals grow from water vapor in the air, just like snow
crystals, but while snow crystals form on suspended dust particles high
in the clouds, frost crystals form on surfaces near the ground -- on
window panes, blades of grass, or just about any other solid object.
Many tender plants can be damaged or killed by such frost, while hardy
species produce certain proteins that move the water in their cells
into out into spaces where ice crystals can form without critical
damage. Some researchers report that what eventually kills these cells
is dehydration leading to their collapse.
Window frost forms when a pane of glass is exposed to below-freezing
temperatures on the outside with moist air on the inside. The water
vapor from the room freezes when it condenses on the inside surface of
the window and as this process continues, the frost develops into what
looks like feathery fingers or ferns. Window frost often makes
elaborate patterns as the crystal growth is strongly influenced by the
window surface. Scratches, residual soap streaks, and dirt can all
change the way the crystals form around a central area and grow. This
phenomenon was more common in the past, when houses still had
single-pane windows, as the double-pane windows are much better
insulators and thus not so cold on the inside surfaces.
Surface hoar typically forms when a snow bank warms up during the day
and is then cooled again overnight so that water can evaporate from
inside and re-crystallize on the surface. By morning the snow
bank is covered with a layer of sparkling faceted ice crystals, and
they can be quite large. In low temperatures, surface hoar can also be
broken apart and blown across the surface. These usually melt again
once the sun comes up, so the best time to find surface hoar is early
in the morning.
Hoar frost should not be confused with rime, which is formed from
freezing fog and deposits as a continuous thick layer of ice, rather
than individual frozen droplets. Meteorologists distinguish between
three basic types of ice forming on vertical and horizontal surfaces by
deposition of super-cooled water droplets: soft rime which is milky and
crystalline and appears similar to hoar frost, hard rime that is more
dense, and clear ice that is transparent. (Glaze ice is similar in
appearance to clear ice but it is the result of a completely different
process, occurring during freezing rain or drizzle.)
Scientists often have to break huge chunks of hard rime off weather
equipment, in order to keep anemometers and other measuring instruments
operating, and rime ice can sometimes accumulate on the leading edges
and control surfaces of an aircraft when it flies through a cloud of
super-cooled water liquid droplets causing potentially disastrous loss
of lift.
English folklore holds that Jack Frost, an elfish creature, is
responsible for the various manifestations of ice crystals,
particularly the feathery patterns of frost found on windows on cold
mornings. In some traditions, he can be fairly harmless, just nipping
fingers, toes, and noses when one ventures outside in the winter, while
in others, he punishes with a frozen death. It seems he was originally
based loosely on a Norse character, named Jokul Frosti (literally
Icicle Frost).
There are similar characters wherever bitter winters are common. Russia
has Father Frost, a character who rewards kindness with rich gifts and
safe passage, and legend tells of an old woman who causes snow by
shaking out her feather bed in Germany. The Saxons had three names --
King Frost, Father Frost and Father Time. This is the character we see
at New Years, when he holds a sickle to represent the death of the old
year. To symbolize new beginnings, he gives over his position to the
newborn Baby New Year. Our best to you and yours in 2012.
---------------------------------------------
January
3, 2011: Orchids
I had almost forgotten how lovely snow can be when large flakes drift
quietly down, sparkling in the beam of the porch light. It transforms
the ordinary into a fairyland, and when they settle on the
multi-colored bits of brightness that decorate the outdoor Christmas
tree, the scene is even more enchanting. It is an interesting
observation that most of our various holiday decorations--tinsel,
ornaments, strings of lights, icicles, whatever--have been inspired by
the effort to recreate the beauties that are freely given us by Mother
Nature.
It seems a strange time of the year to go looking for new plants but
for a few species it is a very good opportunity, as long as the ground
is not obscured under deep snow. All the competing foliage has
shriveled up or disappeared and things pop into view that have been
previously hidden. Mosses and a number of ferns are evergreen, and
there are also other plants that are out all winter, photosynthesizing
on the occasional warm day.
I discovered a new puttyroot orchid right on the edge of one of our
main woodland trails last week. This flower's life cycle is dependent
on utilizing the sunlight that falls upon it after the forest canopy
begins to open up in the fall. As other forest plants grow
dormant, the puttyroot puts out its broad, cold-resistant basal leaf
and starts manufacturing the next year's food supply which it stores in
its roots. This stalkless single leaf is dark green with pale vertical
stripes and appears to be almost pleated as it emerges from the ground.
In the spring the leaf dies back and a foot-tall leafless stalk emerges
with a dozen or so flowers arranged up its height. These are rather
unobtrusive but when examined closely show themselves to be
purplish-green to yellow with a white lip spotted with purple.
While the puttyroot is seldom abundant in the north, it is more common
elsewhere and the glutinous putty that was obtained by crushing the
corms was used at times as a cement, as a treatment for boils, and
evidently most often, as an aphrodisiac or love charm. Its common name
was Adam-and-Eve, a term presumably arising from its growth habit which
includes an underground development of two or more side-by-side corms.
When three were produced, the plant was referred to as
Adam-and-Eve-and-Son.
The orchid family is perhaps the largest in the world of flowering
plants, having more than 25,000 species. They range from plants only a
fraction of an inch high with blossoms about the size of pinheads to
some with ten-foot stems and fifteen-foot flower stalks, but all have
certain common characteristics. As seedling plants they have a single
leaf with parallel veins and flower parts in 3’s or 6’s, and are
related to lilies, bananas, palms and grasses.
The flowers have three sepals in an outer whorl and three petals inside
them, although some of these may be fused or reduced. One of the petals
is different from the others and is often larger and showier. In the
center of the flower is a fleshy column, a fusion of the male and
female reproductive organs. At the top is the anther with its pollen
grains and immediately below is the stigma, a sticky depressed surface
that receives the pollen when carried by an invading insect. Below this
is the ovary which, if fertilized, expands into a capsule containing as
many as a million seeds.
With this prolific reproduction it would seem that orchids should be
very common but the fact is the plants have quite specific requirements
for survival and germination is not often achieved. Consequently, at
least in Wisconsin, all wild orchids are protected by law and property
owners who are fortunate enough to have some on their land usually
treasure them.
I have collected seeds from the beautiful yellow lady slipper orchid on
several occasions, but have had no success in getting them to grow.
Friends from Bluestem Farm in the Baraboo area do propagate wild
orchids, however, germinating the seeds in a sterile medium and then
caring for the tiny seedlings several times before they are ready to be
go into soil. It is time-consuming work but they have been successful
in reproducing a number of species to blooming size.
I have purchased a few of their showy orchids and now have a cluster of
these horticultural gems in my wild garden. Both the showy orchid and
moccasin flower presumably could grow here, as well as several of the
smaller-flowered prairie orchid types, and it will be a challenging and
fascinating project to successfully introduce them.
One of the highlights of our year is Orchid Quest, the annual
mid-winter show and sale of the Madison Orchid Growers Guild. It is
held in the Exhibition Hall of the Alliant Energy Center in Madison,
and this year will be February 3-4, from 10:00 a.m. to 5:00 p.m. on
Saturday and until 4:00 p.m. on Sunday. If you have never attended,
give yourself a treat and you will gain a new appreciation for this
fascinating plant.
----------------------------------------
January 3, 2011
I had almost forgotten how lovely snow can be when large flakes drift
quietly down, sparkling in the beam of the porch light. It transforms
the ordinary into a fairyland, and when they settle on the
multi-colored bits of brightness that decorate the outdoor Christmas
tree, the scene is even more enchanting. It is an interesting
observation that most of our various holiday decorations--tinsel,
ornaments, strings of lights, icicles, whatever--have been inspired by
the effort to recreate the beauties that are freely given us by Mother
Nature.
It seems a strange time of the year to go looking for new plants but
for a few species it is a very good opportunity, as long as the ground
is not obscured under deep snow. All the competing foliage has
shriveled up or disappeared and things pop into view that have been
previously hidden. Mosses and a number of ferns are evergreen, and
there are also other plants that are out all winter, photosynthesizing
on the occasional warm day.
I discovered a new puttyroot orchid right on the edge of one of our
main woodland trails last week. This flower's life cycle is dependent
on utilizing the sunlight that falls upon it after the forest canopy
begins to open up in the fall. As other forest plants grow
dormant, the puttyroot puts out its broad, cold-resistant basal leaf
and starts manufacturing the next year's food supply which it stores in
its roots. This stalkless single leaf is dark green with pale vertical
stripes and appears to be almost pleated as it emerges from the ground.
In the spring the leaf dies back and a foot-tall leafless stalk emerges
with a dozen or so flowers arranged up its height. These are rather
unobtrusive but when examined closely show themselves to be
purplish-green to yellow with a white lip spotted with purple.
While the puttyroot is seldom abundant in the north, it is more common
elsewhere and the glutinous putty that was obtained by crushing the
corms was used at times as a cement, as a treatment for boils, and
evidently most often, as an aphrodisiac or love charm. Its common name
was Adam-and-Eve, a term presumably arising from its growth habit which
includes an underground development of two or more side-by-side corms.
When three were produced, the plant was referred to as
Adam-and-Eve-and-Son.
The orchid family is perhaps the largest in the world of flowering
plants, having more than 25,000 species. They range from plants only a
fraction of an inch high with blossoms about the size of pinheads to
some with ten-foot stems and fifteen-foot flower stalks, but all have
certain common characteristics. As seedling plants they have a single
leaf with parallel veins and flower parts in 3’s or 6’s, and are
related to lilies, bananas, palms and grasses.
The flowers have three sepals in an outer whorl and three petals inside
them, although some of these may be fused or reduced. One of the petals
is different from the others and is often larger and showier. In the
center of the flower is a fleshy column, a fusion of the male and
female reproductive organs. At the top is the anther with its pollen
grains and immediately below is the stigma, a sticky depressed surface
that receives the pollen when carried by an invading insect. Below this
is the ovary which, if fertilized, expands into a capsule containing as
many as a million seeds.
With this prolific reproduction it would seem that orchids should be
very common but the fact is the plants have quite specific requirements
for survival and germination is not often achieved. Consequently, at
least in Wisconsin, all wild orchids are protected by law and property
owners who are fortunate enough to have some on their land usually
treasure them.
I have collected seeds from the beautiful yellow lady slipper orchid on
several occasions, but have had no success in getting them to grow.
Friends from Bluestem Farm in the Baraboo area do propagate wild
orchids, however, germinating the seeds in a sterile medium and then
caring for the tiny seedlings several times before they are ready to be
go into soil. It is time-consuming work but they have been successful
in reproducing a number of species to blooming size.
I have purchased a few of their showy orchids and now have a cluster of
these horticultural gems in my wild garden. Both the showy orchid and
moccasin flower presumably could grow here, as well as several of the
smaller-flowered prairie orchid types, and it will be a challenging and
fascinating project to successfully introduce them.
One of the highlights of our year is Orchid Quest, the annual
mid-winter show and sale of the Madison Orchid Growers Guild. It is
held in the Exhibition Hall of the Alliant Energy Center in Madison,
and this year will be February 3-4, from 10:00 a.m. to 5:00 p.m. on
Saturday and until 4:00 p.m. on Sunday. If you have never attended,
give yourself a treat and you will gain a new appreciation for this
fascinating plant.
-----------------------------------------
December 27, 2011: A New Year
January1st seems like a strange date
to designate as the commencement
of a new year. Certainly the Wisconsin outdoors shows almost no sign of
any beginnings, and much of the wild world is either hunkered down or
fast asleep. One would think that the onset of spring would be a more
logical time to celebrate, and that was true in the past. In 2000 BC,
the Babylonian year began with the appearance of the first crescent
moon after the Vernal equinox (first day of spring). The Romans
continued this tradition, but various emperors tampered with the
calendar until it lost its connections with the sun. In order to right
things, the Roman senate, in 153 BC, declared January1st to be the
beginning of the New Year, and when Julius Caesar, in 46 BC,
established what has come to be known as the Julian calendar, that
practice was continued. January1st has been celebrated as a holiday by
Western nations for only about the past 400 years.
According to the astronomical
calendar, however, we have just entered
the winter season. A week ago, we celebrated the solstice, that day at
which the sun appears to rise at its most southerly point. As a result,
the length of time between sunrise and sunset was at a minimum and we
experienced the shortest day of the year. Earth is actually closest to
the sun in January, but is so oriented that the direct rays of the sun
fall in the southern hemisphere rather than upon us, so we see the sun
low in the southern sky and have short wintry days and long nights.
It is interesting to learn that the
earth has not always had its
present tilt on its axis of 23.5 degrees. It has been as great as 24.5
and as small as 21.5 over a cycle of 40,000 years and it is impossible
to know what effect this has had on our planet. If the north pole were
tilted directly toward the sun during the summer months, the entire
northern hemisphere would have 24 hours of sunlight each day while
winters would be in constant darkness. On the other hand, if there were
no tilt at all, the entire planet would have equal days and nights with
no seasons at all. There is some evidence that even the small
deviations we have experienced have caused significant changes in the
world’s climate through the centuries.
So what is going on in the outdoors
these days? Animals such as the
woodchucks, bats, bears, and chipmunks are hibernating; that is, their
heartbeats and breathing rates have dropped to a near-death status in
their secluded dens. A woodchuck's heart rate goes from 80 beats per
minute to four beats per minute. Squirrels, raccoons, skunks, and deer
mice also disappear during very cold periods but venture out on mild
winter days. These species are not true hibernators but enter a deep
torpor during severe weather.
Snakes and other reptiles begin to
look for a place to hibernate as
early as October -- some species often gathering in large
congregations. Box turtles have been known to bury themselves five feet
into soft dirt or sand to escape the freezing temperatures, while we
know at least some of our rattlesnakes spend the winter in a den deep
under our big rock. Amphibians also hibernate, with toads and tree
frogs burrowing into the ground and aquatic frogs sinking to the bottom
of ponds and lakes.
Just about every wildlife species will
experience some decline in
population over the winter season, even those who migrate to warmer
climes, as the journey is often a dangerous one. Whitetail deer reduce
their metabolism to conserve stored fat energy and have coats with
hollow hairs filled with insulating air, but even then it is estimated
that a winter with very deep snow can kill as much as 30% of the
northern herd. In open country, extended blizzards can wipe out more
than 60 percent of a pheasant population.
The snow also causes difficulties for
shrews, mink, coyotes, and fox
that depend upon small rodents for food. The same snow benefits the
mice and voles, however, as they can live and navigate more safely
under its protection. Even some birds such as ruffed grouse burrow
under the surface for shelter and warmth. In lengthy periods without
snow, subzero cold can drive the frost deep into the soil, and plants,
insects, and small rodents that otherwise would have the protection of
an insulating blanket may not survive.
Of all nature's survival feats, the
most impressive might be that of
winter resident birds such as chickadees who must maintain body
temperatures of 100 degrees or more. Overnight, a chickadee may lose 10
to 15 percent of its body weight, and must spend its daylight hours
feeding constantly to make up. Wild turkeys, on the other hand, can go
for two weeks without eating in periods of severe weather, losing up to
40 percent of their body weight without lasting harm. And it is the
great horned owl that really begins the calendar new year with a flurry
of activity. These large owls are the first birds to nest each year in
Wisconsin, and males start calling and setting up territories as early
as November and December. January is the month of noisy courtship calls
and interesting behavior between the male and female, so step outside
one of these quiet nights and listen in the coming New Year of 2012.
-------------------------------------------
December
20, 2011: Christmas
Conifers
One of the first things we did when we
purchased the farm in the early
70s was to plant some evergreen seedlings around on the
hillsides. During the years that they were growing to a usable
size, we harvested native red cedars for our Christmas trees – one for
the living room and the other for feeding the birds outside. Red cedars
are not the evergreen of choice for home decorating as they lack the
bright green color and fragrance of a pine or spruce and the needles
are prickly and uncomfortable to handle; still, in our enthusiasm for
our new rural home, we didn’t mind.
Despite its name, the Eastern red
cedar is actually a juniper. True
members of cedar family are found only in Asia and Africa but our red
cedar exhibits many of the same characteristics – its wood being
fragrant, colorful, insect-repellent, and lightweight. Larger red cedar
trees provided timber for ships and other buildings, while smaller ones
were used for making furniture, pencils, fence posts, and shingles.
Like most junipers, the red cedar is
very slow growing and moderately
long lived. Trees are either male or female, and in the early spring
the males display tiny tan-colored "pine cones" on their branches.
These release pollen in great quantities that fertilize the small spiky
flowers on the female trees. Fruits are pale-blue ¼ inch
‘berries’ (cones), with a whitish bloom, each containing 1 or 2 seeds.
While not particularly desirable for
indoor decoration, the red cedar
provides food and cover for numerous birds and mammals. The species was
rare in Wisconsin when white men first settled in the area, growing
only in remote, fire-free places such as exposed cliff faces. As fires
were controlled, however, the trees flourished and spread, often
forming thick stands that overwhelmed other plant species. We have
spent many hours trying to hold them in check on our hillsides.
We were happy to switch to the pine
and spruce trees for our holiday
decorations when the ones we planted grew to a height of five or six
feet. Some evergreen plants have broad leaves such as rhododendron and
holly, but most, such as the conifers, have specialized leaves called
needles that exhibit three survival characteristics -- a thick skin, a
coating of waterproof wax, and a simple needle-like shape that reduces
the amount of water vapor that can escape. By having leaves already
present in the spring, evergreens can start photosynthesizing earlier
than deciduous varieties, and can continue to produce food after other
trees have gone dormant in the fall.
Conifers have remained virtually
unchanged for more than 300 million
years, and are often the dominant tree species in more northerly
latitudes, high altitudes, and areas with poor soil. It is thought that
they evolved to retain their leaves because putting out new foliage
each year would require more water and nutrient than is available in
these areas. Most also live in close association with fungi in the soil
to utilize the scarce nutrients more effectively.
Most conifers have also adapted to
cold climates by developing spire
shapes that shed snow. They have a central trunk that grows straight up
with branches that project from the stem in whorls at regular
intervals. Their long-lasting needles also contain substantial amounts
of resins and other relatively inedible compounds that may protect them
somewhat from browsing animals.
The distinctive feature of all
coniferous trees, however, is the cone,
usually a cluster of highly modified woody scales tightly packed
together. Most species produce male and female cones on the same tree
although a few, like the yews and junipers, appear on separate plants.
The inconspicuous male cones are small and drop from the plant soon
after releasing pollen, while female cones enlarge after pollination,
requiring several months to reach maturity for some species, years for
others. Overall seed production will vary greatly from year to year in
any given region, but tends to peak once every 3-6 years. These
infrequent bursts are common among most trees and help to ensure that,
at least occasionally, seed production will exceed the appetites of
hungry squirrels, mice and birds. leaving some to survive and grow.
In those original plantings years ago,
we put in black and white spruce
and red and white pine. The black spruce is more commonly found in
poorly drained swamps but has done well on our dry hillsides and the
white type more typically grows farther north. Both can be
distinguished by their short needles that are attached singly to the
branches in a spiral fashion, and remain on the tree for 4–10 years.
The white pine was once the most important timber species in the state,
and like the red, has longer needles that are bundled in clusters of
2-5. All four species proved to be relatively fast growing but only
were usable for Christmas trees for a few years. Now, the trees are far
too tall and we wondered why we did not have the foresight to add more.
Still, we enjoyed using homegrown trees while they were young, and will
continue to enjoy the rest as they grow to maturity.
---------------------------------------------
December 13, 2011: Snowy Owls
Reports of snowy owls are coming in
from all over Wisconsin, although
none seem to have been seen locally; still, recent sightings include
four birds at the La Crosse airport, and others in Iowa, Chippewa,
Clark, Vernon and Green Lake counties. Ornithologist Bill Mueller tells
the Wisconsin State Journal as many as 100 snowy owls have been
reported already across the state in contrast to the typical winter
when no more than a dozen are spotted. The last time these owls
appeared this far south in such large numbers was in 2006, and Mueller
says if the state has a normal winter, the owls could stay around until
early March.
The snowy is one of the largest
species of owl in North America with a
wingspan of up to 5½ feet, and can weigh up to 4½ pounds.
The adult male is virtually pure white, but females have some dark
markings and the young are heavily barred. The bird has extremely thick
plumage and heavily feathered legs and feet, characteristics that make
it well adapted for its life north of the Arctic Circle. The feathers
also have no pigment, leaving more space for air that gives the owls
additional insulation. Like the related eagle-owls, the snowy has ear
tufts but they are small and usually tucked away.
Snowy owls nest on the Arctic tundra
in Alaska, Canada and Eurasia.
They winter south through Canada and northern Eurasia, with sporadic
migrations occurring further south in some years. They are attracted to
open areas like coastal dunes, prairies and even airports as these must
seem somewhat similar to tundra, and on rare occasions, the owls have
been reported as far south as Texas, Georgia and even the Caribbean.
This species of owl nests on the
ground, often building on top of a
mound or boulder as the bird needs good visibility in its mostly
treeless habitat. Breeding occurs in May, and depending on the amount
of prey available, clutch sizes range from 5 to 14 eggs, laid 2 to 5
days apart. The female starts incubation when the first egg is laid
resulting in staggered hatching, so a group of chicks often ranges
greatly in age and size. Hatching takes place approximately five weeks
after laying, and the young are cared for by both parents.
Snowy owls are unlike most other owls
in that they are active during
the daylight hours as well as at night. They are opportunistic hunters
and will take advantage of larger prey, fish and carrion, and
frequently follow trap lines to find food, but they rely primarily on
lemmings and other small rodents. They are heavy eaters and require the
equivalent of three to five lemmings per day, or up to 1,600 each year.
Lemming populations are notoriously cyclic and in those periods when
lemming populations are down, the owls often leave the arctic regions
and fly south in search of food.
Snowy owls have keen eyesight and
hearing, abilities needed to find
prey hidden under thick vegetation or snow cover. Most hunting is done
in the "sit and wait" style, but prey may be captured on the ground, in
the air or fish may be snatched off the surface of bodies of water.
They, like many other larger birds, swallow their small prey whole.
Strong stomach juices digest the flesh, while the indigestible bones,
teeth, fur, and feathers are compacted into oval pellets that the bird
regurgitates 18 to 24 hours after feeding. Biologists frequently
examine these pellets to determine the quantity and types of prey the
birds have eaten.
Though adult snowy owls have few
predators, they must defend their
nests and nestlings against arctic foxes, dogs, gray wolves and avian
predators. They dive-bomb them with sharp talons and engage in
distraction displays to draw any persistent predator away from a nest.
An adult does have some dangers, however, as one is sometimes struck by
a vehicle, or collides with a utility line and other object. A few are
even shot, and there have been recent reports that these birds are
being illegally killed for their eyes and feet -- hot items in Asian
markets.
The snowy owl has always been
considered special – perhaps because of
its lack of color and its unpredictable appearances in many areas. It
is the official bird of Quebec, Canada, and it was depicted on the 1986
series Canadian $50 note. For the Oglala Lakota Indians, it represented
the north wind and was held in great respect by the tribe; in fact,
warriors that excelled in combat wore a cap of white owl feathers to
symbolize their bravery. Even J. K. Rowling used the bird in her
popular Harry Potter series (Harry had a pet snowy owl named Hedwig).
I have received a number of comments
from readers on the various terms
I have reported that have been used to name groups of birds (i.e.
murmuration of starlings, sieges or sedges of cranes), and so must add
some of the strange names given to a group of owls. The most common is
“a parliament” but look at these others -- a brood, eyrie, hooting,
looming, nest, stooping, diss, sagaciousness, stare, wisdom, bazaar,
and glaring – plus these that are the best – a stable of barn owls, a
jail of barred owls, a prohibition of barred owls, a schizophrenia of
hawk owls, and finally, a blizzard of snowy owls! Can you beat
those?
----------------------------------------
December 6, 2011: A
Collection of Sandhills
Two weeks ago it was a murmuration of starlings that caught my
attention, but for the past month it has also been a sedge of sandhill
cranes, or perhaps you might prefer to use another term, a siege of
cranes. It seems that “sedge” refers to rush-like marsh plants, and
therefore any group of birds that nest among them, while “siege” is
used for groups of herons or cranes that are known to wait patiently
for prey in shallow water. Whatever they are called, there have been
hundreds of the big birds gathering each day in the fields along
Rainbow Road, and they provide quite a sight.
Sandhills are the most common of all the world's cranes. The bird’s
name comes from the fact that huge flocks can be seen at the edge of
Nebraska's Sandhills along the Platte River -- a region of mixed-grass
prairie on grass-stabilized sand dunes in north-central Nebraska. The
adult crane is gray overall with a red forehead, white cheeks and a
long dark pointed bill, although it may appear brown because the bird
preens by daubing mud on its feathers. It weighs about ten pounds, and
has a wingspan of up to six feet. While flying, its silhouette is
distinctive as it stretches its long neck straight out ahead while
trailing its long dark legs behind.
There are two main subspecies – the Greater that stands about 3
½ feet tall and breeds in Michigan, Wisconsin, Minnesota and
parts of Canada, and the Lesser that is somewhat smaller and breeds as
far north as Alaska and Eastern Siberia. The greater sandhill
population was almost killed off in the past two centuries by over
hunting, and by 1940 fewer than 1,000 birds remained. With protection,
their numbers have since increased greatly to more than 100,000
individuals, but they are still less plentiful than the lesser sandhill
crane which numbers over 450,000 individuals, making that species the
most plentiful crane alive today.
Most sandhill cranes live in freshwater wetlands. They eat whatever
they can find -- plants, grains, mice, snakes, insects, and worms. They
also dig in the soil for tubers and can sometimes cause significant
crop damage, which brings them into conflict with farmers. They create
a nest structure from whatever plants may be at hand and typically lay
two eggs, which both parents incubate.
Pairs vocalize in a behavior known as "unison calling." They throw
their heads back and call in a synchronized and complex duet, although
the female makes two calls for every single call of the male. They also
dance, run, leap high in the air and otherwise cavort around—not only
during mating but all year long. A sandhill has an exceptionally long
trachea (up to 2 feet) that is coiled within the hollowed keel of the
breastbone. The bony rings of the trachea fuse with the sternum to
create thin plates and when the crane calls, the plates vibrate. This
amplifies the sounds, which can carry a mile or more.
During migration, lesser sandhill cranes assemble at established
staging areas and stopover points on their way to Texas, California,
Arizona, New Mexico and Mexico. One such place, in the Platte and North
Platte River valleys in Nebraska, hosts the largest gathering of cranes
in the world. About three-fourths of the sandhills that breed from
Alaska and the Canadian plains and mountain provinces pass through the
area and at its peak, the number of cranes on the Platte and North
Platte reaches about half a million.
The cranes that we see here in Wisconsin are greater sandhills that
traditionally spend the winter in Florida, with a major stopover in
northeastern Indiana at Jasper-Pulaski Fish and Wildlife Area. There
they join thousands of other sandhills, resting and socializing before
moving on south. The wildlife area website reported that one day last
week they counted 10,640 birds (I wonder how they do that!).
The whooping crane is a much larger bird – often standing 5 feet tall
with a wingspan of 8 feet. At one time only 15 birds were known
to exist, but with protection and reintroduction their numbers have
increased to some 400. Initially, sandhill cranes were used as
foster parents for whooping crane eggs and young in reintroduction
schemes, but the project failed as these whoopers imprinted on their
foster parents and later attempted to pair only with sandhills.
Since 2001, groups of young whooping cranes have been taught to follow
ultralight aircraft to learn their migratory route between Wisconsin to
Florida. The chicks raised for this project are fitted with plastic
color bands and radio transmitters, which enable researchers to locate
and identify the banded cranes after they are released. The current
class of youngsters has made it into Kentucky at this point and once
they complete their migration, they will be added to the more than 100
adult whoopers that now make up the eastern flock.
Take a drive over to Rainbow road to see these magnificent sandhill
cranes, but don’t delay as one day soon they will stretch their wings
and move south.
----------------------------------------------
November 29, 2011: Pigeons for Thanksgiving?
Last week, one of the major newspapers featured a Thanksgiving feast
that it touted as a “going native” meal. I thought it rather strange
that the writer ignored the fact that wild turkeys roamed the New
England woods when Europeans arrived, but perhaps she did so because
these choice birds had been killed off in most areas of the East by the
beginnings of the 20th century and were only recently being
reintroduced. Still, her choice of young pigeons (squabs) for the main
course seemed rather unusual.
There is really only one native pigeon in most of the country that is
present in any numbers – the mourning dove. ('pigeon' is from French,
pijon, and 'dove' is English, but both names are always used somewhat
interchangeably). The mourning dove is plump-bodied and long-tailed,
with a head that looks particularly small in comparison to the body.
Its call is a distinctive, plaintive cooOOoo-woo-woo-woooo, uttered by
males to attract a mate, and is sometimes mistaken for the call of an
owl. It is abundant and widespread and is also the leading game bird
across the country, with more than 20 million birds shot each year. It
weighs only an average of 4.5 ounces live and even less when dressed,
however, so it would require a number of birds for a Thanksgiving meal.
The mourning dove is considered to be closely related to the passenger
pigeon, another native species that disappeared in the early 1900s.
(For this reason, the possibility of using mourning doves for cloning
the extinct bird has been discussed.) Some estimate that there were 3
to 5 billion passenger pigeons in the United States when Europeans
arrived, although others have argued that their numbers only exploded
after European diseases caused Native American populations to crash
which reduced predation and competition for food. The passenger pigeons
were hunted widely for meat, sport, and by farmers who were protecting
their crops, and the last one died at the Cincinnati Zoological Garden
in 1914.
It is more likely that the author was thinking of using the young of
domestic pigeons for her meal, as these birds are larger and more
easily obtained for the average cook. These are the descendents of the
rock dove -- originally found across Britain, Europe, Central Asia,
India, and up into China and Mongolia. They were domesticated thousands
of year ago as a meat bird and eventually carried to the New World
where escapees quickly established spreading populations. Now their
descendents can be found in almost every farmyard and many city parks,
and domesticated varieties are raised for sport and meat. The adult
pigeon is about 14 in long and can weigh as much as 13 oz., with
iridescence along its neck and wing feathers, and a conspicuous
off-white waxy covering at the base of the upper beak.
Male pigeons fluff their glossy neck feathers, reflecting shimmering
green, bronze, and purple, when courting a female. They spread their
tail feathers and parade in circles while cooing loudly. It is thought
that this courtship behavior may also serve to strengthen the lifelong
bonds of an already-mated pair, as most pigeons form strong pair bonds
and sometimes may remain together throughout the winter.
Doves and pigeons build flimsy nests from sticks and other debris, and
prefer to place them in hard-to-reach places, such as covered crevices
along building ledges or in barns or under bridges. The female lays one
or two eggs, and both parents care for the young, rarely leaving the
nest unattended. When flushed from the nest, an incubating parent may
perform a broken-wing display, fluttering on the ground as if injured.
Unlike most other birds, members of the pigeon family produce "crop
milk", a high-fat, high-protein substance that is secreted by a
sloughing of fluid-filled cells from the lining of the crop. Both sexes
produce this highly nutritious substance to feed to the young.
The baby pigeons grow very fast. They walk well at about 18 days of age
and start exercising their wings about a week later. The birds are
often bigger than their parents by the time they start to fly because
they have been well fed and haven't done much exercising. Pigeons,
especially homing or carrier breeds, are well known for their ability
to find their way home from long distances but wild rock doves are
sedentary and rarely leave their local areas.
Seeds and fruit form the major component of the diet of most of the
family but they also feed on insects, grain, and even garbage. They
generally eat enough to fill their crops and then fly away to digest
while resting, often swallowing grit or sand to help break down the
hard portions. Pigeons are also unique in having the ability to suck up
water, using their beaks like straws, in contrast to most other birds
that have to take small sips and tip their heads backwards to swallow.
The mourning dove has been designated as the Wisconsin symbol of peace,
but that doesn’t save it from being hunted and eaten. Knowing that, and
interesting as we may find the pigeon family, it will always be a
domestic turkey that graces our Thanksgiving table. I am content to
leave the pigeons out in the barn or sitting on the telephone wire
along the road.
----------------------------------------------------------
November 22, 2011: A Murmuratiion
A beautiful video is circulating on U-tube these days showing a huge
flock of starlings wheeling and circling in unison over Ireland's
Shannon River. Such a gathering of these birds is called a murmuration
– a term with which I was not familiar but will not soon forget.
Perhaps you, too, have seen such a display, although probably on a much
smaller scale. One has to wonder how do they do that in such perfect
harmony?
Flocking starlings are one of nature’s most extraordinary sights. Just
a few hundred birds moving in a synchronized display is spectacular
enough, but the flock filmed in Ireland contained thousands. Until
recently, it was hard to say how they managed such maneuvers and
scientists had to wait for high-powered video analysis and computer
modeling to begin to understand, and still find it mind-boggling.
This behavior was first simulated on a computer in 1986 by Craig
Reynolds with his creation, Boids. This program simulates simple agents
(boids) that are allowed to move according to a set of basic rules. The
result is applicable to a flock of birds, a school of fish, or a swarm
of insects. Basic models of flocking behavior are controlled by three
simple rules: (1) separation - steering to avoid crowding local
flockmates; (2) alignment - steering towards the average heading of
local flockmates; and (3) cohesion - steering to move toward the
average position of local flockmates. With these three rules, the boid
flock moves in an extremely realistic way, creating complex motion and
interaction.
There is no leader; instead the flock's movements are determined by the
moment-by-moment decisions of individual birds, since different birds
will be at the front every time the flock turns. Wayne Potts, in the
journal Nature in 1984, reported that any individual can initiate a
change in direction which then propagates through the flock in a wave
radiating outward. Potts proposed that birds farther away from the
initiation site were able to see the wave approaching them, and could
"get set" to move before it actually reached them, allowing almost
instantaneous response.
In the June 14th issue of Proceedings of the National Academy of
Sciences, University of Rome theoretical physicist Giorgio Parisi and
his team studied starling flocks on the outskirts of Rome -- some just
over 100 birds, while others contained more than 4,000. Regardless of
size, the correlations of a bird’s orientation and velocity with the
other birds’ orientation and velocity didn’t vary. If any one bird
turned and changed speed, so would all the others.
Mathematical analysis of flock dynamics showed how each starling’s
movement was influenced by every other starling, regardless of the size
of the flock or the individual’s location in it. This phenomenon is
known as scale-free correlation, and goes beyond biology. The closest
fit to equations describing starling flock patterns come from the
literature of crystal formation and avalanches — systems poised on the
brink, capable of near-instantaneous transformation. In starlings,
“being critical is a way for the system to be always ready to optimally
respond to an external perturbation, such as predator attack,” they
wrote.
Statistical physicists Andrea Cavagna and Irene Giardina along with
their colleagues of the Centre for Statistical Mechanics and Complexity
in Italy, have watched and filmed flocking starlings for three years
from the top of the Palazzo Massimo – Rome’s national museum. They also
concluded that these flocks follow Reynolds’ basic rules. "The clearest
structural feature is that a bird's nearest neighbors are typically
found at the bird's sides, rather than ahead or behind the bird, so
that the probability that a bird's nearest neighbor is approximately
ahead or behind is very low", the authors write. Since the bird's eyes
are on the sides of its head, it sees sideways better.
Surprisingly, the research team found that any particular starling's
orientation and flight speed correlated with the position and velocity
of only its six closest neighbors, regardless of flock size. They
concluded that starlings simply cannot track the movements of more than
six others. (It is also thought that this limitation may to be shared
with humans.)
The team contends that it is easy for a starling to follow when its
neighbor turns but the mechanism which allows it to happen almost
simultaneously in hundreds of birds is still not understood. This may
be important because they feel that the implications may extend far
beyond birds, and that starlings may simply be the most visible and
beautiful example of a universal biological mechanism that also seems
to operate in objects as miniscule as neurons.
Cavagna and Giardina wrote in their research paper, The Seventh
Starling, "Surprisingly enough, in an era in which splitting the atom
into its tiniest parts has become commonplace for science, obtaining
empirical data on large groups of creatures moving in three dimensions
is still a very difficult task".
-------------------------------------------
November 15, 2011: Invasives
Now that most of our woodland trees have dropped their leaves, the
vistas have expanded and we can see the other hills that surround us.
The understory is also almost bare, allowing those plants still
retaining their green foliage to stand out prominently. Half a dozen
small trees caught our attention as we worked to hold back the
ever-expanding stands of prickly ash and berry stalks, and neighbor
Gigi, a specialist in invasive species, confirmed that buckthorn has
now invaded our land. When the snow fell, I feared that I had waited
too long to do something about them, but their leaves still hang on so
I am determined to do them in.
We had already spent an afternoon clearing several new patches of
barberry – another invasive that tries to crowd out every other plant
in its vicinity. We found these while searching for the deer remains
that our collie had discovered and found delicious, and who then had
proceeded to deposit the smelly residue on the living room rug. There
is a large area infested with barberry that we have been fighting for
years on one of the hillsides to the North, but these were the first
plants we had found in the woods by the house.
There are two varieties of barberry – the common (introduced from
Europe and Asia) and the Japanese – and both bear orange-red berries
that are very attractive to the birds and make the plants difficult to
contain. We seem to have the Japanese variety as the leaves have smooth
edges rather than serrated, and the fruits are mostly single rather
than in clusters. Both spread freely, but the common type is more
feared as it is host to a black rust that is very damaging to wheat.
Common buckthorn was also first brought from Europe in the mid-1800s as
a very popular hedging material, as it proved very hardy and thrived in
a variety of soil and light conditions. However, it was found to be
quite invasive in natural areas and although the nursery industry has
stopped selling it, many buckthorn hedges may still be found in older
neighborhoods throughout the upper Midwest. In addition to the common
buckthorn, a glossy type was sold in two different forms – one that is
narrow and tall and the other that spreads up to 10 feet and has narrow
leaves that give it a ferny texture. This buckthorn aggressively
invades wetlands including bogs and sedge meadows.
Common buckthorn leafs out early and retains its leaves late into the
fall. It takes the form of a tall shrub or small tree and can grow up
to 25' high with a spreading loosely branched crown, often showing
multiple stems at the base. Its buds and leaves are opposite and the
twigs often end in sharp, stout thorns. Leaves are egg-shaped, pointed
at the tip and have smooth edges. In addition to the late-hanging
leaves, the best field characteristic is a crop of large, round,
berry-like clusters of black 1/4" fruit that ripens in August and
September.
A common buckthorn produces only male or female flowers and fruiting
trees are always female. Most of the fruits fall directly beneath the
shrubs, creating a dense understory of seedlings characteristic of
common buckthorn stands. The plentiful fruit is eaten by birds and mice
and is known to produce a severe laxative effect, helping to distribute
seeds as they move through the birds, often far from the parent plant.
Both buckthorns tend to form dense thickets, crowding and shading
native shrubs and herbs and often completely overwhelming them. (The
shrub is also an alternate host of the crown rust of oats, which
affects yield and quality.) Common buckthorn prefers lightly shaded
conditions but it also invades prairies and open fields and is tolerant
of many soil types -- sand, clay, neutral or alkaline, wet or dry.
Donning boots and heavy gloves, I will be heading out with clippers, a
bow saw and a container of glyphosate to cut and treat every stem I can
find, hoping to nip this population before it spreads any further.
Chances are, however, that there are many younger plants already
growing that I won’t find, and so I will be repeating this exercise
every fall for some time. Buckthorn seeds in the soil can remain viable
for up to five years so follow up is essential.
Some invasive plants -- barberry, burning bush, shrub honeysuckle,
multiflora rose and oriental bittersweet – are still being sold in
clueless nurseries, and others such as garlic mustard, buckthorn, and
reed canary grass were introduced either intentionally or accidentally
as medicinals or agricultural crops. All landowners, whether rural or
urban, should be aware of the damage these do and refuse to plant them,
while eliminating all possible when they are found. It may be a losing
fight but we hope to preserve areas that are not yet invaded.
--------------------------------------------------
November 9, 2011: Pesky Raccoons
We had no difficulty with keeping the wildlife out of our ripening
sweet corn this summer, as an electric fence holds almost everything at
bay. Our farmer neighbor had no such recourse, however, and his field
of corn to the north which is relatively small and adjacent to the
woods, had considerable damage. No doubt deer and turkeys ate their
share but a two-year study by Purdue University researchers concluded
that raccoons are responsible for 87% of the damage to corn.
The raccoon is often thought to be a close relative of the weasel, but
it is actually more closely related to the panda.
It is highly intelligent and is Wisconsin's only ring-tailed mammal
with a black facemask – distinctive characteristics that make it easily
recognized. It is compact and stocky, about the size of a large cat or
a small dog and has short front legs and large hindquarters. The adult
stands about a foot high and averages about 32 inches from nose tip to
tail, and may weigh about 20 pounds. It usually shuffles along in a
slow lumbering walk but can bound away quickly to a nearby tree and
climb it with ease, and is also a strong swimmer.
A raccoon’s sense of touch is extremely well developed, especially in
the soles of its flat, hairless black feet. It is believed that the
animal dunks objects in water (washes its food) because the nerves on
its feet become more sensitive when wet and can relay more information
about weight, size, texture and temperature. It will carefully inspect
every unusual object or smelly tidbit that catches its eye or nose.
A raccoon can make a variety of sounds from snarls and growls to a
rasping scream. During the warmer months, one will occasionally make a
loud, long, high-pitched whistle that can be heard for over a mile.
This sounds a bit like the call of a screech owl, though much more
harsh. It also will "purrrr" or "churrr".
There is evidence that when Europeans arrived on this continent,
raccoons were mostly found along rivers and in the woodlands of the
Southeastern United States, but the development of agriculture in the
Midwest encouraged their spread northward. Then their fur became a hot
commodity in the early 20th century, leading the Wisconsin Conservation
Department to carry out a major raccoon propagation and release
program. Their numbers exploded starting in the 1940s, and the
estimated number of raccoons in Wisconsin is now about one for each 30
acres of suitable habitat.
A raccoon may roam up to a mile each night in search of food. Its diet
varies throughout the year, but it will eat just about anything animal
or vegetable – insects, small reptiles, amphibians or small rodents,
eggs or nestlings, any ripe fruit or berries, nuts, garbage, carrion,
and row crops such as corn. It is a major predator of turtle eggs, as
well as frogs, crayfish, snails, baby turtles and clams. Anyone with a
garden can attest to the damage one can cause, and it often waits until
just before harvest to raid the corn or melon patches.
The female often selects a hollow tree for her den but may also use an
abandoned burrow, culvert, vacant shed, barn loft, or even an
accessible attic – usually to the distress of the homeowner. A
litter of 3-5 helpless, fuzzy kits are born in April or May. Their eyes
are closed but they can crawl around in the den and they grow rapidly.
They venture outside when they are 8 weeks old and are very curious and
playful. By July, they follow their mother to the nearest source of
food and by early fall, they begin to move off on their own. Half will
die in their first year from vehicles, disease, predators, and hunters.
As autumn approaches, the raccoon builds up fat reserves to carry it
through the cold wintry months ahead. When temperatures drop below
freezing, the each retires to a winter den, curling up in a ball with
its front paws covering its eyes. This long period of winter sleep is
not a state of true hibernation and if temperatures turn mild, it will
often wake up and forage outside for food.
The major causes of death for raccoons in Wisconsin are trapping, motor
vehicle collisions, disease and predation. Many are hit on the roads
when they first emerge from their winter dens and are still a little
drowsy. Also in the summer when mothers are abroad with their unwary
kits, entire families of raccoons are prone to being killed by motor
vehicles. They also are host to a wide variety of diseases and
infections. Parvovirus, canine distemper, and rabies are responsible
for many raccoon deaths and they also can suffer from tuberculosis,
pneumonia and encephalitis.
Hunters and trappers play an important role in controlling raccoon
numbers, and some 95,000 are taken around the state each year. This is
fortunate because there are not enough large predators to prevent
overpopulation, a situation where rampant disease and nuisance
complaints could make life difficult for the raccoons and their human
neighbors as well.
-------------------------------------------
November 1, 2011: And Then There Were Crows....
The avian sunrise serenade of the past
six months has been replaced by silence, broken only by the raucous
conversations of our local crow family. They seem to find good hunting
in the field to the west and each morning at least half a dozen of the
birds spend several hours scouring the cut hay field for their
breakfast while others of the group talk about it.
Crows have had bad reputations
throughout history as most European traditions viewed them as bad omens
of trouble and death. They are commonly partnered with witches and
bats, and even today, few people have anything good to say about
them. Only the Native American traditions recognized their
intelligence and ingenuity and told stories of them as tricksters. We
have enjoyed their presence in the pines along the road, and husband
Bill always reported that they greeted him on his walks with the dog.
He has a very realistic crow call and they probably consider him a
rather strange looking cousin.
The American crow is big, black, and
makes a lot of noise. It is also probably our most intelligent wild
bird, having its own language with more than 20 sounds and the capacity
to count up to four or five. Their “caws” may be long or short, loud or
relatively soft, given singly or in sequences, and made by one bird
alone or by two or more. Observers have noted that crows use specific
sounds for alarm calls, assembly calls, distress calls, as well as
variety of others. They also imitate other birds and animals, including
even the human voice, but more of interest to researchers are their
many other quiet vocalizations. One problem in interpreting these
calls, however, has been the fact that different groups of crows,
belonging to the same species but in different areas, may not use or
understand the same calls.
Crows rebuild their nests each year --
big, messy stick structures – and each breeding pair has a home
territory, averaging about 10 acres in the city and much larger in the
country. They usually mate for life, and families tend to stick
together. Older offspring may help build the nest, feed the parent bird
sitting on the eggs, tend the hatchlings, or chase away predators, and
since young crows wait at least two years before breeding, family
groups can have as many as 15 members. They move around during the
winter depending upon the availability of food, but stay in the
vicinity of their breeding territory. Crows have only one successful
brood a year as it takes up to four months from egg until the young are
independent.
Most wild American crows live for
about seven or eight years and will eat almost anything --
invertebrates of all types, carrion, scraps of human food, seeds, eggs
and nestlings, and grains such as corn and wheat. They will scavenge at
landfills, scattering garbage in the process, but they are also active
hunters and will prey on mice, frogs, and other small animals. In
winter, the diet is more likely to include nuts and acorns. The crow is
one of only a few species of bird that has been observed modifying and
using tools to obtain food. They disgorge pellets containing the
indigestible remnants of their meals as do owls, and one can often look
under a crow roost and find the large, cohesive objects consisting of
small lumps of grain and gravel with lots of hair to hold them
together.
As I was writing this, a hullabaloo in
the big maple above the deck drew me out to see what was going on. It
seemed the racket was centered on a young red-tail hawk that had taken
refuge there, and several crows were announcing the fact to the world.
The conventional wisdom about such behavior is that crows behave in
this way because they are protecting their nestlings and territories
and have learned that 'mobbing' distracts the hawk so it can't hunt and
will leave the area.
One wonders why the red-tailed (or an
owl, eagle, or other hawk) – a predator quite capable of grabbing and
killing a crow – would allow itself to be pestered? Some experts guess
that if it is not hungry it very well may not find an agile crow worth
chasing, and prefer to just ignore the fuss or else move on to another
area. It would be a very different situation if the hawk was guarding
its nest and had a family to protect, but the fact is, ornitholigists
report that crows never venture onto a predator’s home ground.
It has also been noted that sometimes
a group of crows and a hawk seem to be playing, and Bill watched such
an occurrence from the living room window. The birds circled, tumbling
and twisting in what must have been mock battle, because when the
appearance of a passerby interrupted them, they all settled in a nearby
tree side by side. A quick search on the Internet found many
similar stories, proving again that bird behavior is more complicated
than we imagined.
American crows have proved very
vulnerable to West Nile virus infection. This was originally a
mosquito-borne African virus causing encephalitis in humans and
livestock since about 1000 AD, and was accidentally introduced to North
America in 1999. It is estimated that the crow population around the
country has dropped by up to 45% since then, and in one locality, 72%
died in a single season. Because of this, American crows are considered
a sentinel species indicating the presence of West Nile virus in an
area, allowing the human population to take extra precautions. The
birds cannot transmit the virus to humans directly, and we can only
hope that these interesting birds will survive this threat.
---------------------------------------------
October 25, 2011 ...and Bats: Oh, No!
Some historians tell us that the
ancient Gaels believed that one night
each autumn the boundary between the worlds of the living and the dead
would dissolve and the deceased would come back to life. In an effort
to protect themselves, they would build huge bonfires to push back the
darkness and celebrate around them. Presumably, the nighttime
gatherings attracted clouds of flying insects, which in turn brought
all the resident bats swooping and feeding over their heads, and the
little creatures became symbols of the evil and death threatening them.
When the Romans invaded the area, they merged the local festival with
the Catholic All Saint’s Day on November 1st and Halloween came into
being with its symbols of ghosts and bats.
The bat was a natural for this role as
many people find it threatening
and ugly. It has a mouth full of sharp teeth and it wraps itself in its
wings at rest, looking much like a witch or goblin. A bat commonly
swoops about as it looks for insects, and may find the area around
one’s head particularly good hunting. It flies only at dusk and during
the night, and so has commonly been associated with things that are
dark and evil. This was especially true after it was learned that a few
species dine on blood, although most bats eat insects or fruit.
Some bats lead solitary lives while
others live in caves inhabited by
more than a million animals. Their oldest known fossils are from about
50 million years ago, and the bats already looked very similar to
modern insect-eating species. About 70 percent do live on insects while
some of the smaller species are important pollinators of some tropical
flowers. One species has the longest tongue of any mammal relative to
its body size, allowing it to reach down into deep blossoms. When the
tongue retracts, it coils up inside the rib cage. Much of the bad
reputation of our Wisconsin bats comes from their infamous cousin, the
vampire bat. The only mammal that feeds on blood, this native of
Central and South America uses sharp incisor teeth to break the skin in
order to lick up blood from its often-unwitting victim.
While bats have excellent vision, many
insect eaters rely on their ears
for navigation and finding prey at night. Human hearing ranges from
approximately 20Hz (cycles per second) to about 20,000Hz, but bat calls
generally range well above this. By emitting a series of ultrasounds
that generally sweep from a high to low frequency, bats can distinguish
objects and their prey as the echoes are bounced back to their
sensitive ears, and therefore can avoid the object or catch the insect.
This is the process of echolocation -- ability they share with dolphins
and whales.
The most distinguishing physical
features of a bat are its forelegs
that have evolved into wings. The flattened finger bones are very
flexible as their cartilage lacks calcium and other minerals near the
tips, allowing them to bend easily. The skin covering their fingers is
elastic and can stretch, providing wide wing surfaces. Most mammals
have large oval cells in their skin that contain sensory nerve endings,
but on bat wings, each has a tiny hair in the center, making it even
more sensitive. Another receptor cell that is found on the wings of
many of the species is sensitive to the stretching of the membrane, and
may indicate to the bat that an insect has hit its wing.
Female bats usually have only one
offspring per year, and the pup
clings to her fur as she flies until it grows too large and must be
left at the roost. The ability to fly is inborn, but at birth the wings
are too small for use. Young insect-eaters become independent at the
age of 6 to 8 weeks, while the fruit eaters often lag until they are
four months old. A single bat can live over 20 years, but the bat
population growth is limited by the low birth rate.
Wisconsin has seven species of bats,
some of which are year-round
residents, while others move south when the weather becomes inclement.
The little brown bat, the Northern myotis, and the big brown bat
typically hibernate in caves or other protected spots, with the big
brown more tolerant of cold conditions than other Wisconsin bats and
the only one that commonly over-winters in walls and attics. The
silver-haired bat, red bat, hoary bat, and Eastern pipistrelle migrate
to warmer climes before hibernating.
Only half of one percent of bats carry
rabies but they are natural
carriers of several other worrisome viruses and bacteria and it is wise
not to touch any animal that might be sick or injured. Still, their
value in insect control far outweighs any risk of disease they might
transmit. If a bat is found in your house the best technique for
getting it out is to close all the doors and windows to the room except
one to the outside. Most will quickly leave if given the chance.
All hibernating bats (but particularly
the little-brown) are feared to
be at risk due to the appearance of a strange new fungus disease.
White-nose syndrome has already killed more than a million bats since
being detected in New York in 2006, and the disease is spreading
westward. The Wisconsin DNR says survey crews have found no sign of the
disease, but the fungus associated with white-nose syndrome has been
added to the list of prohibited invasive species and the little brown
bat, big brown bat, northern long-eared bat, and eastern pipistrelle
were added to the Wisconsin threatened species list. Hopefully, these
steps will help save these important and interesting animals.
-----------------------------------------------
October
18, 2011: Warblers and Such...
Those perky sparrow-like birds hopping around on your porch or deck
this past week or flitting about in your bushes are very likely not
sparrows at all, but yellow-rumped warblers on the go. Their relatives
having been moving down from the northland the past month or so,
escaping the onset of winter, and these are often the last to pass
through.
They are called yellow-rumped because, as you might guess, all have
patches of bright yellow above their tails, even in their winter and
juvenile plumage. Summer males are more colorful, with yellow crowns
above black cheeks, black streaked breasts and yellow patches along
their sides just in front of their wings. Many migratory species,
particularly those breeding further north, have distinctive male
plumage at least in the breeding season, since males need to reclaim
territory and advertise for mates each year.
The yellow-rumped is one of some 120 species of small songbirds in this
hemisphere that are dubbed wood warblers. They range up to 7 inches in
length, and live in forest, brush, or swampy grass country. It is
likely that they originated in northern Central America, and this area
still houses the largest number of species. They spread northward
during the periods between the glaciers, mainly as migrants, and still
return to the ancestral region each winter.
The name “warbler” might lead one to think that these birds have lovely
voices, but many have only weak, lisping songs. The yellow-rumped
warbler has a short high-pitched, whistling trill that drops the last
two or three syllables. It also uses a sharp “chek-chek-chek-chek” and
“psit-psit-psit” calls to communicate with others in its flock.
The yellow-rumped is perhaps the most versatile forager of all these
little birds. It’s the one you are most likely to see fluttering out
from a tree to catch a flying insect, and it is also quick to switch
over to eating berries in fall. It has been observed snatching insects
out of a spider web, and grabbing flies off piles of manure. All
warblers eat mainly insects in the summer, including caterpillars,
beetles, ants, scale insects, aphids, grasshoppers, and gnats, as well
as spiders. They are important allies during outbreaks of forest pests
such as spruce budworm and tent caterpillars. On migration and in
winter they eat great numbers of fruits, particularly juniper berries,
poison ivy, poison oak, greenbrier, grapes, Virginia creeper, and
dogwood. These birds do not come readily to feeders, but they will
visit backyards where suitable brush and mixed trees are available to
host insects.
Their feeding and nesting habits resemble those of so-called old world
warblers – an entirely separate family. Those comprise almost 350
species that closely related to the thrushes and flycatchers, and are
found in Europe, Asia and Africa. Only a few of these birds, such as
the kinglet and gnatcatcher live in the Americas.
In 1758, Carolus Linnaeus developed a classification system for all
animals, and divided them into groups that had things in common. Then
he split those into smaller groups and when he finally finished, there
were seven levels in his system. His scientific classification system
is still used today. Here is how scientists classify a yellow-rumped
warbler: Kingdom: Animals; Phylum: Animals with backbones; Class:
Animals called birds; Order: Birds that perch; Family: wood warblers;
Genus: highly-colored warblers; Species: yellow-rumped warbler.
As scientists learn more about birds, they have been able to more or
less arrange the 10,000 species by Order, Family and Genus although
there has always been a surprising amount of debate about some. For
example, about twenty years ago scientists decided that the Baltimore
oriole of the Eastern United States was really the same bird as the
Bullock's oriole in the Western United States. They renamed both birds
“Northern oriole”. Then, in 1995 after conducting DNA comparisons, they
decided these really were two separate species after all.
Today there are many scientists investigating birds, and scientific
classification is undergoing a big change. Dr. Charles Sibley, a past
president of the International Ornithological Congress, did research
for over twenty years using DNA testing and suggested a new way to
classify the birds of the world. He contended that some species were
more closely related than anyone thought and rearranged some of the
Orders and Families in a way that was quite unexpected. Research
continues, and this autumn big changes are being put into place and new
names applied.
Unless you are an avid birder and watch the worldwide activities of the
ornithologists, you probably have little interest in the finer points
of bird classification but getting acquainted with a variety of species
is an interesting and rewarding hobby. We have listed more than 120
species that have visited our farm through the years, and are always on
the lookout for new sightings.
--------------------------------------------------
October 9, 2011: Sulfur Shelf:
"Chicken of the Woods"
What kind of organism is a fungus?
Certainly not a plant, although
until recently even scientists believed that was the case. However,
most fungi build their cell walls out of chitin, the same material as
the hard outer shells of insects, and plants do not make chitin. Now it
has been determined that they are more closely related to animals, and
have been placed in their own Kingdom. The body of the fungus is made
up of a web of microscopic filaments that are buried in the soil, in
wood, or in another food source. These webs live on and grow unseen
until they develop mushrooms, puffballs, truffles, brackets, cups,
“birds nests,” “corals” or other fruiting bodies.
The fruiting bodies often seem to
sprout up overnight. They can do this
because when they begin to enlarge they already contain their full
complement of structural cells. It requires only a heavy rain to fall,
at which time the fungus body pumps water into these cells, and almost
overnight some mushrooms can go from pin head size to full size.
Generally, we avoid picking the
numerous mushrooms we find along our
hiking trails as we don’t have the expertise to be confident in
identifying the edible varieties. Two exceptions are the morel and the
sulfur shelf. Most Wisconsinites are familiar with the morel, but
unless you frequent the woods you may not have seen a sulfur shelf.
This large fungus, which is also known as “chicken-of-the-woods”,
announces its presence with a bright orange top and gorgeous sulfur
yellow underside. Called a bracket or shelf mushroom because of the way
it extends from a tree trunk, the sulfur shelf is often found on or
around an oak tree and often comes back year after year. This year, we
discovered a huge specimen growing in the farmyard on our old willow.
Young sulfurs are moist, rubbery, and
easily broken, while more mature
specimens become pale, tough, and are often dotted with insect holes.
Many think that the texture and even flavor is reminiscent of chicken,
but those who would like to try it should be aware that, as with any
mushroom, some individuals have a bad reaction, including
light-headedness and nausea. "The neat thing is that it's impossible to
misidentify," said Greg Mueller, curator of mycology at Chicago’s Field
Museum. "It's the only big, bright orange bracket mushroom with sulfur
pores growing on wood out there." This was pretty much the accepted
wisdom well into the 1980′s, but as allergic reactions seemed to become
more numerous, it was found that specimens growing on certain trees and
in certain areas sometimes did cause problems and gastric distress.
Eucalyptus, evergreens, and locust in particular were suspect and the
advice now given is to avoid any sulfurs collected from these trees.
The sulfur shelf grows in large
flattened fans that lie in horizontal
tiers, sometimes becoming huge and weighing as much as a hundred
pounds. It is more accurately called a polypore because, rather than
having gills underneath its cap like many other mushrooms, it has
tubes, or pores -- tiny holes dotting the underside. These are lined
with spore producing organs, as fungi must produce enormous numbers of
spores so that at least a few will land on favorable surfaces for
germination.
All polypores have two or three kinds
of cells -- the rapidly expanding
inflatable generative cells, along with two kinds of reinforcing cells,
referred to as ‘binding’ or ‘skeletal’. The hard woody conks you see on
trees have all three and will persist on their hosts for several years.
The sulfur shelf has but two -- the quickly expanding (and edible)
generative type, and the more rigid, slower growing binding kind. These
latter cells give the fruiting body strength and rigidity and can even
hold it together for a time after the softer tissue dries out and
collapses.
The sulfur may grow inside a tree for
some 50 years in order to build
up enough energy to form the colorful fruiting bodies, and during that
time the fungus is feeding upon the tree's inner tissues, causing
decay. All wood is composed mostly of two substances -- cellulose which
is white and forms the primary wall of all plant cells, and lignin
which makes up the brown inner wall in some cells, especially those of
trees.
Polypores, such as the sulfur shelf,
harbor both brown rot fungi that
degrade only the white cellulose leaving the brown lignin to crumble to
dust, and white rot fungi that decompose the lignin and leave the white
stringy cellulose behind. As the decay proceeds, hollows are created
that house all sorts of creatures, and eventually the fungi will
accomplish the transformation of the tree into soil.
Meanwhile, springtails, nematodes, and
other tiny beings graze on the
fungi inside the tree, while fungus gnats, fungus flies, pillbugs, and
various fungus beetles feed on the shelf fungus itself and are in turn
picked off by birds. These fungi play an important role in the health
and vigor of the forest but harvesting their fruits will cause no harm,
and we can enjoy discovering the eye-catching color amidst all the
green, and have it for supper, as well.
----------------------------------------------------
October 4, 2011: The Awesome Butterfly
A few weeks ago our garden was alive
with butterflies. Giant and tiger
swallowtails were sipping nectar from the zinnias and phlox, monarchs
were visiting the milkweeds, and we had to watch where we stepped on
the gravel drive to avoid the red-spotted purples and tiny crescents
and azures that were under our feet. Now those are all gone and the
only hangers-on are the fritillaries and the ubiquitous cabbage
butterfly.
Almost everyone is familiar with the
cabbage “worm”. It is not uncommon
for a gardener to find one flying around in the kitchen as its
caterpillar often hides among the leaves of any of the harvested cole
vegetables – broccoli, cauliflower, cabbage or the like – and creeps
off to hide in a corner. There it pupates and in two weeks or so it
emerges a butterfly, ready to reproduce again wherever it can find a
food plant for its larvae.
Most people would consider the
fritillary to be a much more desirable
insect. The top surfaces of its wings are a brownish-orange with wavy
black lines and spots, but if you take the time to look at the
underside of its wings (visible when the butterfly pauses and holds
them closed over its body) you will see that they are covered with
metallic silver spots. Chances are you have never seen the caterpillar
of one of these beautiful insects, as it feeds only at night and then
near the ground on violet plants.
The large, usually colorful wings are
what transform these otherwise
rather ugly insects into objects of beauty. A butterfly has four wings,
two fore and two behind, attached to the middle segment of its body.
Strong muscles move them up and down in a figure-eight pattern during
flight, allowing some insects to reach speeds of 12 miles per hour and
a few to travel 1000s of miles.
Butterfly wings are composed of two
thin transparent layers of chitin,
a protein that also makes up the outer surface of the body, and are
nourished and supported by a network of tubular veins. These veins are
extensions of the body's circulatory system and are filled with a fluid
that serves much the same function as does blood in a bird or mammal.
Within each of the major veins are also a nerve and a trachea (a fine
tube that conveys air directly to the tissues).
Covering the wings are thousands of
tiny plate-like overlapping hairs
called scales, which create the colors and patterns we see. These
scales contain melanins that give them black and brown colors, but the
blues, greens, reds and iridescence are usually created not by pigments
but their crystalline nature that scatters the light striking them,
separating the colors. The scales cling somewhat loosely to the wing
and come off easily without harming the butterfly.
Still, scales are very important to
the butterfly. They form patterns
that help their bearer to find a mate, as well as protect itself by
blending into the background, mimicking another more dangerous
creature, or warning of bad taste. It is thought that they evolved
initially for providing insulation on wings and body, as dark colored
scales would absorb sunlight, and they are also thought to help
increase the lift-to-drag ratio in gliding flight. Scent scales are
modified wing scales on male butterflies that release pheromones to
attract mates.
Part of the secret as to how an
earthbound crawling caterpillar can be
transformed into a flying insect was revealed when researchers found
that the larvae have four tiny developing wing disks under the skin in
place of the spiracles that are apparent on the outside. Before the
last molt, these increase dramatically in size and connect to tracheae
in the body in the beginnings of the wing veins. They even begin to
develop the patterns that will later decorate the adult wings.
When the caterpillar is fully mature,
it will attach itself to a twig
or other firm support with silk and hang motionless for a day or so.
During this time, the wing stubs are forced outside the skin by
pressure from the body fluid, and by the time the skin splits and falls
away, they have adhered tightly to the outer cuticle of the chrysalis.
Within hours, the new outer surface hardens and it is possible to see
impressions of the miniature wings, as well as the head and antennae,
legs, and abdomen of the adult butterfly. This chrysalis is usually
incapable of movement, although some species can wiggle the abdominal
segments or produce sounds to scare potential predators. Inside, the
wing stubs become pleated and compressed from top to bottom as they
grow, so that they can be rapidly unfolded to their full size.
When the adult butterfly emerges from
its pupa, in several weeks or
perhaps the following spring, its delicate wings are crinkled, wet, and
uninflated. It hangs upside-down and pumps fluid into the wings to
inflate them, and then must wait for several hours for the wings to dry
and harden before it can fly. Who among us is not awed to witness such
a transformation!
--------------------------------------------------
September 27, 2011: Woodchuck or
Groundhog
The wild creatures around the farmyard
are well aware of the presence
of a big noisy collie, but tend to go about their business in relative
safety – mostly I would guess because she is indoors during the
nighttime hours when most are active. The woodchuck (or groundhog as it
is often called) that lives in the shed under the woodpile is quite
bold, however, now that apples have been falling from the tree a short
distance from its doorway. It sticks its head out cautiously and scans
the area for the dog, then makes its way over to the windfalls and
helps itself. The sight of the chubby animal sitting up with an apple
in its paws and munching away always amuses us, and we don’t begrudge
the few it eats.
The woodchuck usually grows to about
two feet in length with short,
powerful legs and a bushy tail. It can weigh as much at 15 pounds in
the autumn just before going into hibernation but will lose much of
that during the winter and weigh considerably less in the spring.
Mostly vegetarian, it likes fruits and vegetables of all kinds, but
when these are scarce, it will eat grasses, clover, tree leaves and
flowers. Like all members of the squirrel family, it has ever-growing
incisors that must be kept worn down and sharp by constant chewing.
Woodchucks are known for their complex
vocalizations, involving a
series of whistles, squeals and barks. Most noticeable among these are
high-pitched squeals that are usually emitted to alert others of a
predator, but they also make guttural barking sounds and low clicking
sounds with their teeth.
Woodchucks are protected by Wisconsin
law and there are no specified
hunting or trapping seasons, although landowners may hunt or trap them
on their property. Apparently, the original reason for protecting them
was their value in creating homes for other small animals such as
rabbits that hunters valued for sport. When North America was first
settled, woodchucks were relatively scarce, but as forest areas were
cleared and fencerows and meadows increased, the chuck's range
expanded. Now, this species is common except where a high water table
prevents digging. A woodchuck can move as much as 700 pounds of dirt in
the construction of its burrow that can reach five feet below ground
and extend length-wise for thirty feet or more.
The female produces a single litter of
three or four young in May. The
youngsters are born blind and hairless but are weaned by late June or
early July, and soon after strike out on their own. The life span of a
woodchuck is usually about 3 to 6 years if they survive to adulthood,
and they seldom range more than 50 yards from their den once they
establish a territory. Adult animals are quite capable of defending
themselves, but young ones are preyed upon by hawks, owls, coyotes,
badgers, weasels, and dogs. Highway traffic takes a heavy toll on the
animals of all ages.
By the end of October, most woodchucks
are curled up in a profound
sleep in their underground nest. So deep is this condition that even if
the animal is warmed up, it requires several hours to awaken.
Woodchucks are true hibernators and usually sleep all winter, although
individuals may awaken during periods of mild weather.
Woodchucks are subjects for research
because they have dramatic annual
biological rhythms driven by hormonal signals caused by fluctuations in
the hours of daylight. The cycles are so strong that even in the
laboratory, where the temperature is maintained at 70 degrees
year-round with ample food and water, some woodchucks still stop eating
and hibernate. Human cycles, like those of woodchucks, are most likely
also affected by photoperiod, although exposure to artificial lighting
may confuse the results. Scientists hope that by studying the body
functions in the woodchuck, they can better understand the underlying
changes in human brain chemistry, body metabolism and hormone
secretion.
One interesting study by Penn State
biologist Stam Zervanos showed that
male woodchucks routinely arouse toward the end of winter and suggests
that they emerge temporarily to find females. He reports that the pair
gets acquainted but then both go back to their separate dens to sleep,
evidently satisfied that they have their mates secured. At the proper
time, they awake again and mate – the male sometimes visiting several
females before returning to his solitary lifestyle. Zervanos says that
although the woodchucks may appear half-dead, "they seem to maintain a
biological rhythm even during hibernation".
This habit of early emergence led to
the idea that a woodchuck’s
appearance was an late winter omen of spring . The most widely known
woodchuck is Punxsutawney Phil, a Pennsylvania resident of the town
library who eats dog food and ice cream. For 120 years, on
February 2nd, he (and his predecessors) has been pulled out from under
a fake tree stump and asked to predict the coming of spring. It is said
he does so speaking in ‘Groundhogese’, and he seldom errs. In
Wisconsin, we have own prognosticator in Jimmy The Groundhog of Sun
Prairie. Our Timbergreen members of the family may not be famous but we
enjoy them anyway, even as we watch them snack in our garden.
__________________________________________
September 20,
2011: Snakeroot and Indian Pipe
We had a delightful group of third and fourth graders from the Lone
Rock Elementary School visit us at the farm this past week, and their
energy and enthusiasm for all things they saw – living trees and
lumber, the 2000 year-old Native American cave-shelter on the hillside,
our pond and the things they found in it, and the giant swallowtail
caterpillar that stuck out its scent glands with its surprisingly
potent odor – and endless questions were challenging.
We hiked through the woods but saw few wildflowers, as most have
bloomed and formed seeds by this time of year. Still, two very
different plants still displayed their blossoms – the white snakeroot
and Indian pipe.
White snakeroot is a native plant common throughout the area that can
be found blooming in open woodlands through September and October.
Numerous flower heads are grouped into loosely-branched, flat-topped
clusters and each small flower head is about 1/4 inch wide and contains
up to 30 bright-white disk flowers. After blooming, small seeds with
fluffy white tails will be released to blow in the wind. Early settlers
gave it its name as they thought its underground tubers removed toxins
from snakebites, but modern medicine has not been able to prove any
such ability.
On the contrary, white snakeroot contains the toxin tremetol that is
poisonous to horses, goats, sheep and cattle. When the plants are
consumed by dairy cattle, the meat and milk can become contaminated and
may poison any humans who eat or drink them. Milk of cows that had fed
on snakeroot caused milk sickness, and during the early 19th century,
when large numbers of immigrants settled in the Midwest, many thousands
died. Notably, milk sickness was the suspected cause of death in 1818
of Nancy Hanks Lincoln, mother of Abraham Lincoln.
It was some decades before the cause of the illness was traced to
snakeroot, although today Dr. Anna Bixby is credited with identifying
the plant in the 1830s. Legend has it that she was taught about
the plant's properties by a Shawnee woman as she and her people had
extensive knowledge of the herbs and plants in the area. In the 1920s,
a U.S. Department of Agriculture study agreed that snakeroot contained
a substance that caused milk sickness and dairy farmers were ordered to
keep it out of their fields and their cows fenced. Today, it is highly
unlikely that snakeroot will get into cow’s milk.
The other blooming flower is very different but is easy to recognize.
Indian pipe grows only five or six inches tall and has tiny, scale-like
leaves and a single curled over flower on top of each stalk. It is
often thought to be a fungus as it has a waxy, whitish color, but this
is because it has no chlorophyll, a green pigment found in almost all
plants that allows them to obtain energy from light. Indian pipe cannot
make its own food and has to obtain nutrients from another organism,
and to do this, it establishes two special relationships -- one with a
tree, and one with a fungus, taking nutrients from both at the same
time.
It does this by tapping its roots into the root-like threads (mycelia)
of a fungus which itself has invaded the roots of a tree. Many fungi
and trees have this type of relationship; the fungus gives nutrients to
the tree and the tree gives nutrients to the fungus. Indian pipe,
however, takes nutrients from the fungus itself, and it also takes
nutrients that the fungus had received from the tree and does not give
anything back to either. It. Since it is not dependent on sunlight to
grow, it can exist in very dark environments as in dense forest.
Indian pipe can only establish relationships with certain species of
fungi and trees, but much is still be learned about them. It is known
that they use Russula and Lactarius fungi, two common, fairly large and
brightly colored mushrooms whose distinguishing characteristics also
include brittle free white gills and the lack of any encircling tissue
on the stem. The lactarius also emits milky latex when its gills are
broken. Trees that have been found to be essential to these mushrooms,
and thus the Indian pipe, are oak, beech and birch.
Indian pipe is a food source for small bumblebees, which visit the
flowers for nectar. They pollinate the blossoms and tiny seeds form, at
which time the plants turn black. The seeds need very special
conditions to germinate so it is a real treat to find these strange
plants.
Other flowers are blooming out in the prairies – asters, blazing stars,
sunflowers, gentian, sneezeweed, and lobelia – but these two forest
plants are welcome breaks from all the green of the woodlands. Color is
beginning to show on the Virginia creeper and sumac, however, and soon
the hills will be ablaze with reds and yellows. Enjoy it while you may.
--------------------------------------------
September
13, 2011: The Elusive Weasel
When we walk through the fields and
woods at this time of the year
there are far fewer living things in evidence now that almost all the
breeding and rearing of young has been completed. Still, there are
hints of continuing activities if you are alert, -- a raised tunnel
across the trail, a partially eaten hickory nut, a couple of feathers
or a tuft of fur discarded along the way, a snake skin, tree and shrub
leaves peppered with holes, an abandoned bird nest, hoof prints in the
dirt.
An animal we almost never see but
think may be a full time resident on
the farm is one of the weasels. There are two species in Wisconsin –
the long-tailed and the least weasel, both members of a large family
that also includes the mink, marten, fisher, badger, river otter, and
skunks. The distinctive characteristic all of these share is that
they possess muscular glands under the tail that are capable of
emitting sulphurous volatiles that are very effective in repelling
attackers.
We have seen tracks of the least
weasel in the winter and had fleeting
glimpses of one. It has brownish fur with white underneath in the
summer, but it turns all white in November. It is the smallest of the
family -- less than ten inches in length plus a 2-3 inch tail and
weighs less than 8 ounces. It has a long slender body and very short
legs and these give it a distinctive running gait, as at every bound
the long body loops upward, reminding one of an inchworm. The least
weasel has a large territory and males may roam over 35 acres while
females usually remain within less than 10 acres. Weasels feed
predominantly on mouse-like rodents and young rabbits and are adapted
for pursuing prey down tunnels, though they may also chase prey from
their burrows, killing them with a bite to the back of the skull or the
neck.
The least weasel, like others in its
group, does not dig its own den,
but nests in the abandoned burrow of some other animal such as a mole
or rat, relining the nest chamber with straw and the skins of its prey.
It mates in the spring, and in a month, the female produces a litter of
around 6 kits, that are less than a tenth of an ounce in weight and
naked, blind and deaf. At four days, they gain a white coat of downy
fur and they are weaned at 2–3 weeks of age. The eyes and ears soon
open, and by 8 weeks, they are already killing prey their parents
provide.
The long-tailed weasel prefers mixed
habitats near streams or small
rivers and some authors report finding them only in places with
abundant water. They also are commonly found along roadsides and around
farm buildings where mice are plentiful, however. The long-tailed has a
home range of 30 to 40 acres, and population densities vary with season
and food availability. In favorable habitat, there may be up to 18
long-tails per square mile but this fluctuates considerably with
year-to-year changes in prey abundance.
This weasel has a black tip on its
tail, a characteristic that is
thought to confuse some predators as they focus on it instead of the
animal itself. Hawks, owls, eagles, foxes, coyotes, bobcats, and
domestic cats as well as other members of the weasel family will eat a
weasel – provided they can catch one. They are extremely agile and
their long and slim bodies make it easy for them to escape into small
holes. They are also able to follow their prey into burrows, and their
needle-like canine teeth are designed to pierce the throat or brain of
small animals.
Long-tailed weasels mate in late
summer, mostly from July through
August. It is an interesting fact that there is a long delay in the
implantation of the fertilized egg in the uterus, and the young are not
born until the following spring, (a gestation period of almost 9
months). A typical den is a burrow that may be 10 feet long and have
two openings several feet apart. Average litters consist of six young
that are blind and naked at birth. Their eyes open in about 5 weeks but
at 3 months of age they are fully grown.
Weasels are easiest to detect in
winter when leaf cover is gone and a
thin layer of tracking snow reveals their whereabouts in the
neighborhood. They leave staggered pairs of little footprints placed in
a bounding gait fashion and their intense curiosity and insatiable
appetite leads them to range widely in a seemingly erratic fashion. A
weasel will stop to poke its little head into every hole, nook and
cranny it can find.
The ferret is another weasel-type
occasionally seen in our area, but it
is always a domesticated animal that has been released or has escaped.
Weasels and ferrets have similar body shape and size and are both are
carnivorous and crafty, but ferrets have a long history of making
interesting and entertaining pets while weasels seldom become
tame. Weasels are sometimes blamed for killing chickens, but
their value in helping control rats and mice around the farmyard far
outbalances any damage that they might do. Most of the time, we humans
never know that a weasel lives nearby.
-------------------------------------------------
September 6, 2011: Katydids
In my daily sweeps through the garden,
yard, and nearby areas in a
search for Japanese beetles, I have scared up several large green
fluttering creatures that go by the strange name of ‘katydids’. These
grasshopper-like insects usually stick to the treetops but these had
ventured down perhaps in search of more tender leaves to eat. When they
do come to the garden they are seldom seen as their oval-shaped wings
are marked with veins making them look much like green leaves with legs.
The katydid name has an interesting
origin. In the summer of 1743,
Pennsylvania botanist John Bartram wrote in his journal, "The great
green grass-hopper began to sing (Catedidist) these were the first I
observed this year." Meriwether Lewis spelled it “chittediddle” in his
1804 record of the Lewis and Clark expedition. The name has also been
spelled kittledee, kittydid, and cataded, among others, in attempts to
imitate the sound.
All those names have faded out in
favor of ‘katydid’ for the simple
reason that the term is made up of familiar English words. All katydids
don't sound alike, however, so that led to this traditional
explanation: “Some of the insects say ‘Katy did,’ others ‘Katy didn't.’
Neither side wins the argument, but it gives them an excuse to argue
all night.” Another story goes like this: “A young girl named Katy told
a fib, then compounded the lie by saying she hadn't lied. When she
died, her conundrum lived on in this insect's late-night debate whether
Katy did or Katy didn't tell the lie. Most say Katy did.”
The katydid song serves a function in
courtship, which occurs in late
summer. The bottom surface of one of its front wings has a small ridge
with fine teeth, while the top surface of the opposite front wing has a
long hardened ridge without teeth. As the insect closes its front wings
the file glides along the scraper causing tiny membranes in the wings
to vibrate causing their typical sound. Both male and female emote,
although the male is much the better singer. He starts to call from a
chosen perch as darkness falls and the female’s ‘ears’ that are
situated on her forelegs direct her toward to the loudest singing male
as she replies in the same manner.
The female lays eggs in the ground or
in plant tissue and then dies as
autumn advances, leaving the eggs to hatch in the spring. Young
katydids are called nymphs and look similar to wingless adults, but it
takes three to four months for the nymph to reach adult size, shedding
its skin each time it grows too tight. With its last molt, it acquires
wings and is ready to mate and begin the cycle again.
You may not recognize the katydid
song, but almost everyone knows that
of the cricket. There are some 900 species of this common insect and
they live in both fields and woodlands – anywhere there is the decaying
plant material and fungi upon which they can feed. People with wood
burning furnaces sometimes find that one or more has taken up residence
in their basement woodpile and will entertain them off and on during
the winter.
The sound emitted by crickets is
commonly referred to as chirping and
in contrast to the katydids, only the male crickets sing. A large vein
runs along the bottom of each wing, covered with teeth much like a comb
and the chirping sound is created by running the top of one wing along
the teeth at the bottom of the other wing. As he does this, the cricket
also holds its wings up and open, presumably so that the wing membranes
can act as amplifiers.
There are several types of cricket
song: a loud calling song that
attracts females and repels other males; a quiet courting song is used
when a female cricket is near; and a strident aggressive song triggered
by the close approach of another male cricket.
Crickets chirp at different rates
depending on their species and the
temperature of their environment. Most species chirp at higher rates
the higher the temperature is (approximately 62 chirps a minute at
13°C in one common species although each species has its own rate).
They also have tympanic membranes located just below the middle joint
of each front leg, as do the katydids, which enables them to hear
another cricket's song.
It is a challenge to identify the
songs of most of the species of the
grasshopper family as many are very similar and barely audible. Still,
now that most of the birds have reduced their vocalizations to little
more than occasional calls and the frogs are silent, they let us know
that much is still going on in the wild world, even though autumn is
almost upon us.
-----------------------------------------
August 29, 2011: Calling all Snakes!
We almost stepped on the little snake
as it slithered down the sidewalk
in front of the house. It could not have been more than 10 inches long
and no thicker than the diameter of a lead pencil, and when I picked it
up it was easy to see its orange-red belly as it wiggled and squirmed
to get away. Aptly named a red-bellied snake, it is a common resident
here at the farm and we see one on the road or other open surface every
so often.
Red-bellied snakes spend much of their
time underground or under logs,
boards, rocks, or debris but come out to hunt their prey of slugs,
earthworms, and beetle larvae. Small as they are, they give birth in
late summer to 7 or 8 live young and these must be something to see as
they are only 3-4 inches long. (Only the timber rattlesnake, garters,
ribbon, queen, water and brown snakes also bear their young alive while
all the others lay eggs.) The young snakes develop quickly and can
double their length in their first year and become mature in their
second.
There are some 20 species of
non-poisonous snakes in Wisconsin and we
have seen half a dozen here on the farm. The largest and most
impressive is certainly the bull snake, a reptile of “special concern”
in Wisconsin. (This designation is given to populations of species in
the state whose numbers have dropped considerably in recent years, but
have not yet reached levels considered “threatened” or “endangered”.)
The bullsnake often reaches five feet in length and has a yellowish
body with over 40 large, dark, body blotches that turn into dark black
bands or rings on the tail. Bullsnakes favor open sand prairies, but
since only a small percentage of these remain, they now are to be found
in fields adjacent to bluffs and woodlands. They feed on small mammals,
killing larger prey by constriction and simply swallowing smaller prey
alive.
Bullsnakes emerge from hibernation in
April and breed in May. Once
fertilization has occurred, their eggs begin to develop and when fully
formed are covered by a pliable leathery shell. The female then
deposits a clutch of about a dozen eggs in a protected damp, and
usually dark place, often along with eggs from other bullsnake females.
These hatch into foot-long grey babies in August. Baby snakes have a
tiny, sharp projection called an egg tooth on their snouts that they
use to slice a hole in the eggshell so they can poke their way out. The
egg tooth disappears soon after the snake hatches, but the yolk sac
that nourished the unborn snake is often still present. Bullsnakes
retire into hibernation in October into mammal burrows, sometimes alone
or to share their hideaways with other species.
The 2-3 foot hognose is also a
“special concern” snake. It is unique
because of its sharply upturned nose, which earned it the name and
which allows it to dig into the dirt, but also for several interesting
behaviors. Hognose snakes will usually attempt to escape if threatened,
but when cornered, these snakes perform an elaborate display that
includes fanning out their necks, puffing up their bodies, and hissing.
If this doesn’t work, they will roll over and “play dead”. This display
is often accompanied by vomiting and defecation, which causes them to
smell, and look, like a dead animal. Toads are their preferred food,
and it is thought that their elongated rear fangs may help puncture and
deflate toads during the swallowing process (toads tend to inflate
themselves to avoid being swallowed by predators). These snakes
also have saliva that is mildly toxic, and they are quite harmless to
humans.
In Wisconsin, four snakes are
currently classified as “endangered”,
meaning that they are on the verge of extinction. These are the queen,
the massasauga, and the western and northern ribbon snakes. The timber
rattler is classified as a “protected animal”, the Butler’s gartersnake
is “threatened”, and five are designated “species of special concern”
besides the bullsnake and hognose: western wormsnake, North American
racer, northern and prairie ring-necked, and grey rat snake.
Fascinating facts about snakes: all
must rely on their surroundings to
control their body temperature, so in the heat of the summer, they hide
underground or crawl into cool spaces with lots of vegetation. On cool
days, they will lie out in the open where the sun can warm them. All
Wisconsin snakes are predators and eat anything from sowbugs to other
snakes. Their meals include such things as mice, snails, earthworms,
salamanders, spiders, voles, frogs, young squirrels, and leeches. If
the prey is too large to swallow alive, most non-venomous snakes kill
their prey by wrapping their coils around the animal and tightening
until it can no longer breathe.
Other facts: snakes “smell” by tasting
the air with their tongues; they
have no eyelids and cannot blink; they shed their skins several times a
year; snakes can climb trees, swim, and race, often using their long
rectangular underside scales to catch on stones, branches and other
irregularities on the ground to help them move. Snakes perform an
important service in holding down the populations of rodents and other
harmful creatures and should never be killed. Even the poisonous timber
rattlesnakes are shy reclusive creatures and as long as we watch where
we step on the hillsides, we are pleased to have them as
neighbors.
-------------------------------------
August 22, 2011: Pesky Burs
Sometimes it seems as if Mother Nature
is out to get us – or perhaps
just to keep us conscious that it’s a wild world out there. Ticks,
chiggers, mosquitoes, gnats, and flies attack and bite us when we
venture out-of-doors, and burs grab our clothing and skin and hold on
so tight it sometimes takes a major effort to get ride of them. Most of
the plants that are blooming in the woodlands during the summer and as
well as many out in the fields seem to have one thing in common; they
depend on mobile creatures such as ourselves and our pets to spread
their seeds, and have developed a variety of insidious means to hitch
rides.
Certainly the best known of the
bur-forming plants is the burdock with
the cocklebur close behind. The burdock is an alien biennial that
produces a rosette of very large leaves in the first year and a
branched six-foot stem with many lavender flowers during the second.
Cocklebur is a native annual that usually grows about three feet high
and has relatively large, long-stemmed triangular leaves, and two kinds
of flowers – one that grows on short terminal branches produces only
pollen, while the other that occurs in clusters in the axils of the
leaves, produces seed. Both are members of the sunflower family, and
have one-seeded fruits (burs) that are covered with long spines which
are hooked at the tip. Burdock burs are rounder and have softer, more
Velcro-like hairs than cocklebur. Cocklebur burs are oblong and have
hooked spines on the bur, and have two spines on the end that are
larger and not as strongly hooked.
Besides these two, there are a number
of other “burred” plants on our
farm with which we are all too familiar. In our woodlands we see Sweet
Cicely, a plant with attractive fern-like leaves and white flowers,
that forms black needle-like seeds that not only are sharp but also
possess barbs that cause them to work deep into the flesh of their
hosts. We have found these nuisances almost completely buried in our
dogs’ skins. The plant is reminiscent of anise and smells much like
licorice.
Another bothersome plant is agrimony,
which is rather gangly and grows
up to two or three feet high. The leaves are compound with deeply
toothed leaflets that have little leaflets interspersed between the
larger ones. Long slender flowering stalks bear a line of
multiple tiny yellow flowers during the summer that mature into
cone-shaped seed capsules. The problem is that these are equipped with
a ring of crochet hooks at the wide end that will dislodge at the
slightest touch and latch onto the fur or clothing of any passerby.
Rough avens is a native perennial
plant with light green stems that are
covered with coarse spreading hairs. The lower leaves often are made up
of five leaflets while the upper ones are usually three-parted or
simple. The upper stems end in hairy stalks supporting one to three
½” white flowers, each consisting of 5 petals and 5 triangular
green sepals around a large cluster of green carpels. Each flower is
replaced by a cluster of small, dry, one-seeded fruits that have sharp
hooks that can cling to the fur of mammals, feathers of birds, and
clothing of humans.
Possibly the most abundant of the
sticky-seeded plants is the tick
trefoil, a legume that has alternate compound leaves and a central stem
that ends in an long raceme of up to a dozen pale purple pea-shaped
flowers. These are replaced by flat seedpods about 1-3" long that are
rounded on both the upper and lower sides. The surfaces of these are
covered with hooked hairs that can cling to clothing or fur, and
individual segments can break off and cling to more than one passing
carrier.
An interesting story goes with these
descriptions. One day in 1948, an
amateur Swiss mountaineer and naturalist, George de Mestral, went on a
walk with his dog and returned home covered with burs. He inspected one
through his microscope and saw numerous small hooks clinging to the
tiny loops in the fabric of his pants. It gave him the idea for a
two-sided fastener, one side with stiff hooks like the burs possessed
and the other side with soft loops like fabric. He thought it might
rival the zipper and named it Velcro®, a combination of the words
velour and crochet.
Mestral's idea was met with resistance
and even laughter at first, but
he worked with a weaver at a textile plant in France, and perfected his
"hook and loop fastener." This design was finally patented in 1955, and
today his company, Velcro Industries, is a multi-million dollar
company. Talk about silk from a sow’s ear...
-------------------------------------------
August 15, 2011: Doodlebugs and
Chiggers
Writers for horror films have often
used insects as inspiration to
spice up their movies, sometimes enlarging them to monster size to
enhance the effect. In the Star Trek II film, "The Wrath of Khan!" they
used a large scale-model of a little doodlebug, and most viewers
probably didn’t realize that this remarkable creature really exists.
Properly called an ant lion, the tiny insect makes funnel-shaped,
crater-like pits in soft dirt or sand, and then waits patiently at the
bottom to ambush any hapless passer-by that happens to fall in.
This doodlebug is the larva of a
winged insect that looks much like a
damselfly, and has an enormous pair of sickle-like jaws with several
sharp, tooth-like hollow projections that pierce the victim. These
inject venom that dissolves the prey’s body contents into a liquid that
can then be sucked up. Ant lions seek out dry, sunny spots sheltered
from wind and rain that has sand or light soil that is easy to move.
Pushing itself backward, the larva first inscribes a circle on the
ground. Then, digging deeper and deeper, it spirals in toward the
center, throwing the dirt out with its long jaws.
When a crawling insect, such as an
ant, inadvertently falls into the
pit, it is virtually impossible for it to scale the loose sand on the
steep walls. To make matters worse, the waiting ant lion flips up more
sand, thus deepening the pit and causing a miniature landslide that
knocks the struggling ant to the bottom and its open jaws. In contrast
to the movie and fortunately for us and other mammals, this larva grows
only to ½ inch in length.
When it is fully grown, the doodlebug
moves deeper into the sand to
construct a cocoon. It extends its heavy abdomen and extrudes white
silken threads that glue the sand grains into a hollow sphere around
it. When the cocoon is completed, the larva transforms into a pupa
where it remains for several weeks or over the winter. When the pupa
hatches, the transformed insect breaks through the wall of the sand
cocoon and pushes itself up to the surface.
It climbs up onto a nearby branch or
twig and hangs until its wings are
expanded and dry, and then flutters away in search of a mate. At this
point, it is about 1 ½ in. long with a wingspan of about 3 in.,
and has two pairs of long, narrow, many-veined wings and a long,
slender abdomen. It can be easily distinguished from a damselfly,
however, because it flies only at night and has longer, clubbed
antennae. An adult ant lion may eat small flies or drink water, but its
real purpose now is reproduction, and it lives only long enough to mate
and lay eggs.
While ant lions are only an oddity for
humans, the larvae of another
tiny predator do attack us at this time of year. The chigger is less
than 1/150 of an inch in diameter and almost invisible to the unaided
eye, although when several cluster together their bright red color
makes them easier to see. A single pass through infested grasses and
weeds can collect dozens of these mites on one’s clothing or bare skin.
Chiggers have long legs and can move
rapidly over a person's body in
just a few minutes but usually stay on clothing until they come to an
easy opening such as cuff, collar or waistband. When they find skin,
they insert their tiny specialized mouthparts into skin depressions,
usually at skin pores or hair follicles and inject saliva that contains
a powerful digestive enzyme that literally dissolves the body cells. It
is this liquefied tissue that the chigger sucks up for food. Left
undisturbed, it will alternately inject saliva into the bite and then
suck up liquid tissue for several days, gradually creating a bigger and
bigger itchy welt.
After feeding on its host, the larva
drops to the ground and becomes a
nymph, then matures into an adult that has 8 legs and feeds on plant
materials. The females lay 3–8 eggs in a clutch, usually on a leaf or
under the roots of a plant, and die by autumn. It is only the early
stage that causes us grief.
If you are as sensitive to chigger
bites as I am, you may be interested
in these tips that I gleaned from the internet and plan to try in the
future: chiggers are most active in afternoons when the ground
temperature is between 77 and 86 degrees. Wear tightly woven socks and
clothes, long pants, long sleeved shirts, and high shoes or boots.
Change clothes as soon as possible, and wash them. Regular mosquito
repellents will also repel chiggers but I read that powdered sulfur is
by far the most effective repellent.
Still, I read that the best precaution
against chigger bites is simply
taking a warm soapy bath with plenty of scrubbing as soon as possible.
Attached chiggers are evidently removed by even the lightest rubbing
and you can remove chiggers before they do much damage by frequently
rubbing down with a towel or a cloth. Good luck!
-----------------------------------------
August 9, 2011: Tiger
Swallowtails
It takes only about a month for a
butterfly to develop from a tiny egg
to an incredible flying machine. Its early life is spent as an
elongated bag with legs looking nothing like its adult self, and its
incredible appetite is often so particular that it may starve if not
provided with a specific type of greenery. It grows so quickly that its
skin cannot keep up with its increasing girth and must split and be
discarded four or five times. The final molt reveals an entirely
different object – a soft, legless, wingless thing that hardens into an
unobtrusive pupa or (more properly) a chrysalis.
Inside the seemingly inert pupa, an
almost unbelievable transformation
occurs, and when complete – sometimes in a week or two or sometimes not
until the following spring – the adult insect emerges from its casing
and spreads its delicate wings. Each wing is made up of a membrane
supported by a network of hollow veins and covered with thousands of
miniscule scales that form the patterns that identify each species. The
new creature no longer eats leaves, but extends a tube-like tongue to
sip up the nectar that it finds inside the flower blossoms in our
gardens.
Our largest butterflies are members of
the family called swallowtails
because they have projections on their hindwings that look a bit like
the long, pointed tails of -- what else? -- swallows. We typically see
three species, although a few others – the spicebush, zebra, and
pipevine -- occasionally make an appearance. Relatively common are the
black swallowtail that grows up on plants of the carrot family, the
giant swallowtail whose larvae feed upon the prickly ash that is such a
nuisance in our woodlands, and the tiger swallowtail.
You can easily identify the Eastern
tiger swallowtail by its size and
its bright yellow color, with black striped markings on its wings and
body. The outer edges and lower portions of its wings are also black
and marked with iridescent blue and orange. The tiger is found
throughout the country and feeds on a variety of plants, but in
Wisconsin its most frequent food plant is the wild black cherry tree,
although one sometimes feeds on other members of the rose and citrus
families.
Overwintering pupae hatch in May, but
the largest numbers of tiger
swallowtails are usually seen when their offspring mature in late July
and early August. We see these beautiful insects flitting about in our
flower gardens but sometimes they can be found on the ground sucking up
moisture in damp spots. Males particularly participate in this behavior
that is called puddling, during which they obtain the sodium ions and
amino acids that they need for reproduction. Females will occasionally
puddle, but are seldom seen in groups. Dung, carrion, and urine also
attract them.
The male releases perfume-like
pheromones to attract any passing
females. When one responds, the pair join in a frantic aerial dance,
then land on a branch and mate. Soon, the female begins to search the
area for a place to lay her eggs. She uses her well-developed senses of
smell and taste to find a suitable food plant, using the receptors
located in her antennae and feet. When these tell her she has found a
good spot, she moves about laying her tiny green eggs one at a time
until they are all gone.
In approximately ten days, the
caterpillars chew their way out of the
eggs and almost immediately begin to eat the leaves of the host plant.
Young tigers are brown and white and are thought to resemble bird
droppings (camouflage?) but by the time they have molted several times
they have green skins with two black, yellow, and blue eyespots behind
their heads. At this stage they often hide inside a curled up leaf in
such a way that an intruder might mistake the eyespots for those of a
snake and presumably be frightened off.
Swallowtail caterpillars also have
another unique protective device.
Each possesses an osmeterium, an orange, fleshy organ that emits a
foul-smelling repellent chemical. Normally hidden, the osmeterium is
located on the first segment of the thorax just behind the head, and
can be pushed out when the caterpillar feels threatened. The sudden
sight of these twin projections is startling and presumably resembles a
forked snake tongue.
When the caterpillar reaches its full
growth, it will fasten its tail
to a tree trunk, wooden post or other support with silk, and spin a
thin silk girdle to support itself in an upright position. After a day
or so, it will molt a final time, revealing a green or dark brown
chrysalis that has two horn-like projections on the head and another on
the thorax. If this occurs early in the summer, the butterfly
will continue to develop and hatch in two or three weeks, but if there
is not sufficient time for the developing butterfly to mature, the
chrysalis will go into hibernation and remain there until spring.
Butterflies are an added bonus to our
yards and gardens, providing food
for other creatures, pollinating our plants, and adding pleasure to our
lives. I have always found them fascinating and hope you do, as
well.
--------------------------------------------------
August 2, 2011: Bird Brains
We have been blessed with a
particularly spectacular blueberry crop
this year, but found that we have had to erect a netting tent over the
whole area to keep any for ourselves. It did not take the robins and
catbirds very long to find chinks in our armor, however. They did have
two minor mishaps – one caught its leg in the netting, and another
couldn’t find a way out and had to be rescued – but otherwise these
avian marauders come and go almost at will. They are much too smart for
us.
Another bird behavior we often exclaim
about is that of the
hummingbirds when we allow their feeders to empty. They have been known
to peer in the kitchen window where we are sitting at the table and
demand attention. Just how intelligent are these “bird brains”?
Avian brains got their bad reputation
a century ago from the German
neurobiologist Ludwig Edinger who concluded that without a six-layered
cortex such as humans possess, birds could not possibly be intelligent
and their brains only allow instinctual behaviors. This view is still
found in many biology textbooks, but Dr. Harvey Karten, a
neuroscientist at the University of California, San Diego, is
challenging it.
“There is a bird way and a mammal way
to create intelligence”, Dr.
Karten said. “For example, in mammals, sensory information - sights,
sounds, touch - flows through a lower brain region called the thalamus
and enters the cortex at the fourth layer in the six-layered cortex. In
birds, sensory information flows through the thalamus and enters
specific clusters that are functionally equivalent to the fourth layer.”
Anatomically, a bird has a relatively
large brain. Most species have
large eyes with excellent vision and sensitive ears, and some also have
good senses of smell and touch. They communicate with each other using
visual signals as well as through the use of calls and song, but
scientists have found it difficult to or measure or even define their
intelligence.
Meanwhile, anecdotal examples of bird
intelligence continue to emerge
from observers worldwide. Researchers at the University of Cambridge in
England found that relative to its body size, the crow brain is the
same size as that of the chimpanzee. New Caledonian crows create
complex tools with their beaks and feet, trimming twigs to fashion them
into hooks. Some have been known to make spears out of barbed leaves
that they use to probe into holes for prey.
The ability to count has long been
considered an indicator of
intelligence. E.H. Hoh wrote in Natural History magazine about diving
birds called cormorants used by Chinese fishermen. (Perhaps you have
seen pictures of the tethered birds that dive for fish and bring them
back to the boat, but are prevented from swallowing them by rings
around their necks.) The fishermen allow the birds to eat every eighth
fish they catch and the writer reported that once their quota of seven
fish was filled, the birds would not move again until their neck ring
was loosened and they received their fish. "One is forced to conclude
that these birds can count up to seven," he wrote.
At a university campus in Japan,
carrion crows line up patiently at the
curb waiting for a traffic light to turn red. When cars stop, they hop
into the crosswalk, place walnuts from nearby trees and then wait for
vehicles to crush the hard shells.
Californian crows have also been
observed dropping walnuts onto a
well-traveled road after evidently seeing nuts fall naturally from an
overhanging tree. The crows already knew about dropping clams from a
height on the seashore to break them open, but found this did not work
for walnuts because of their soft green outer shells.
Some birds have amazing memories.
Clark nutcrackers can hide up to
30,000 seeds and recover them up to six months later. Furthermore, if
they see another bird watching them as they cache food, they return
later to rehide it. In a laboratory, researchers found that
chickadees would not cache seeds in the presence of potential thief (a
red-breasted nuthatch that they had previously seen pilfering their
seeds), and choose instead to hide them in the presence of dark-eyed
juncos that don't normally raid food caches, indicating that they could
distinguish between species and were well aware of the threat from the
nuthatches.
Today, in the journal, Nature
Neuroscience Reviews, an international
group of avian experts insists that nearly everything written in
anatomy textbooks about the brains of birds is wrong. They argue that
the avian brain is as complex, flexible and inventive as any mammalian
brain. Certainly some birds are naturally smarter than others, but
given their wide range of behaviors we are just beginning to understand
that birds are far more complex than we ever imagined. They assert that
a reanalysis of avian brains gives new credibility to many behaviors
that seem odd coming from presumably dumb birds, but everyone agrees
that there is still much research to be done.
-----------------------------------------------------
July 28, 2011: Beauiful
Beetle Pests!
Insects commonly lay large numbers of
eggs, as predators eat the great
majority of their offspring before they can mature to reproduce. It is
usually only when a species is introduced into a new area where no such
controls exist that numbers skyrocket and cause damage. Take the
invasion of Japanese beetles, for instance:
The original population was detected
in New Jersey in 1916, and the
pests have gradually moved westward through the country. The adult
beetles are known to feed on over 400 species of broad-leaved plants,
and emerge from the ground in the middle of the summer. The first
beetles out of the ground seek suitable food plants and begin to feed,
releasing a pheromone (chemical) that attracts others. After the
females mate they burrow into the soil to lay a few eggs and then
return to feed and then mate again. This cycle of feeding, mating and
egg laying continues until each female has laid 40 to 60 eggs.
The hatching larvae feed on a wide
variety of underground plant roots
including those of ornamental trees and shrubs, garden and truck crops
and turf grasses, tunneling deeper in the winter and then returning to
the surface as the soil temperature warms come spring. The mature grubs
form pupae in June and emerge as adults a few weeks later. We saw our
first individuals only a few years ago in this area and now, in spite
of running a beetle collection several times a day throughout the
season, we have literally thousands of the insects around our farmyard.
Despite our disgust at the damage they
inflict, it is hard not to be
impressed by their striking appearance. The adults are a brilliant,
iridescent green color, their wing covers are copper-brown and they
have a row of five tufts of white hairs on each side of the abdomen. I
even considered trying to create a mosaic by gluing their dried bodies
to some object or another, but decided I had better things to do.
Such brilliant color seems strange
because, unlike birds, the beetles
rely on chemical attraction instead of showy hues to attract mates. It
also might seem that the colorful appearance of these beetles would
advertise their presence to predators although it is important to
understand that what those hunters discern may be entirely different
from what we see. Entomologists point out that the leafy environment
the insects inhabit is often lit up by flashes of sunlight as breezes
blow and the glistening surfaces of these beetles may blend in well
with those surroundings.
Many insects, including the Japanese
beetles, show iridescent colors.
Iridescence is an optical phenomenon in which a hue changes as the
angle of view or the angle of illumination changes. When talking about
iridescence, it helps to remember that light is a wave and can be
described by its wavelength (the distance between identical points on
the wave). Waves can also be described by their phase -- the position
of their crests (high points) and troughs (low points). When two waves
are in phase, their crests and troughs would match if placed on top of
one another. If the phase of the two waves is different by some
multiple of one full wavelength, the two waves are said to have
constructive interference and this is what happens in iridescence. It
causes the two waves to complement each other and strengthen the
reflection, and creates more intense colors than ordinary pigments ever
could.
Constructive interference amplifies
the colors of a butterfly's wings.
As small as they are, butterfly wings are covered by thousands of
microscopic scales split into two or three layers, and each scale also
has multiple layers separated by air. When light hits the different
layers, it is reflected numerous times, and the combination of all
these reflections causes the very intense colors that you see in many
species. Some butterfly displays even extend into the ultraviolet
spectrum, which is visible to butterflies but not to humans.
The outermost surface of iridescent
beetles is made of many stacks of
slanting, plate-like layers, which are oriented in different directions
and can act as a reflection diffraction grating. These layers bend, and
then reflect the incoming light in the same way and produce structural
colors by interference in the same way as the scales on butterfly
wings. A layer of pigment below the refractive plates of beetles often
enhances the effect of the iridescence although the exact mechanism of
the structural color for many species is an open topic of research.
Most insect structural colors are in
the green-blue-violet range, but
red, gold, and copper colors may also be produced. The shade of color
and its intensity are determined by several factors, including the
thickness and spacing of the layers of the scales, the number of these
layers, and the angle of the incoming light. Possibly the most
spectacular beetle in our area is the dogbane beetle – a native insect
that is much better behaved than the Japanese beetle and is found only
on that wildflower. Perhaps knowing a bit about these various showy
insects makes them easier to tolerate in the garden although I will
admit that it has not changed my opinion of the pesky ones.
July 21,
2011: When a Berry Isn't a Berry
In our younger days, we were
enthusiastic about harvesting the native
fruits that grow on the farm -- spending hours collecting raspberries,
blackberries, elderberries, and even mulberries. We ate our fill and
then froze the rest, later processing them into jams or adding them
into muffins or pancakes.
First to ripen were the raspberries.
We never found many of the red
variety, even though there is a native species that reportedly can be
found throughout the Midwest, as well as a European type that has
escaped into the wild. The two species are difficult to tell apart as
the most distinctive physical difference is the presence of
gland-tipped hairs on first-year canes on the native plant.
Both red raspberries have perennial
root systems that put up biennial
stems – that is, each cane lives two years. In its first year, a new,
unbranched stem grows quickly to its full height of five or more feet,
bearing large compound leaves with five or seven leaflets. In its
second year the stem produces side shoots that bear smaller leaves and
racemes of white flowers. (A raceme is a simple bloom cluster such as
the lily of the valley in which the flowers are borne on short stalks
at equal distances along a stem and open in succession from the lowest
to the tip).
Botanists tell us that the raspberry
is not a berry at all, but a
cluster of individual fruits they call drupelets around a central core.
A drupe is a fruit in which its flesh is enclosed in a skin and
surrounds a hardened shell with a seed inside. In raspberries, the
drupelets separate from the core when picked leaving a hollow, in
contrast to most of their relatives where the drupelets are firmly
attached to the core.
While we seldom see red raspberries,
we have great numbers of black
raspberry plants – locally called blackcaps. The black raspberry is
closely related to the red raspberries, sharing the distinctively white
underside of the leaves and fruit that readily detaches from the core,
but differing in the ripe fruit being black, and in the stems being
more prickly. The black fruit makes them look like blackberries, though
this is only superficial, with the taste being unique and not like
either the red raspberry or the blackberry.
Black raspberries are high in
anthocyanins and have proved to be very
useful as natural dyes and, since anthocyanins are powerful
antioxidants, of a great deal of interest in them for their potential
value in medicine. Extensive work has been ongoing at Ohio State
University to evaluate their benefit for cancer treatment, and the
first clinical trials on patients with esophageal cancer are in
progress.
Researcher Gary Stoner recently joined
the Medical College of Wisconsin
in Wauwatosa, bringing his work on the value of black raspberries from
Ohio State. His team removes the juice, freeze-dries the berries and
grinds them into a powder that is then given to patients with
precancerous lesions. They found that the treatment works on areas it
actually touches like the mouth and esophagus, thought not through the
blood stream and not on full-blown cancer. "They increase your ability
to detoxify carcinogens. ... They reduce oxidative damage from free
radicals," Stoner said.
Mature blackberry plants form a tangle
of dense arching stems, the tips
of the branches rooting where they reach the ground. Vigorous and
growing rapidly in woods and in hedgerows, blackberry shrubs tolerate
poor soils, readily colonizing wasteland, ditches and vacant lots. The
flowers on blackberries are more showy than those on raspberry canes
and may be pale pink or all white. The fruit is also much larger and
ripens after the other berries have gone. Blackberries must be pulled
from their stems as the drupes are firmly attached to their cores. The
stems usually have numerous short curved very sharp prickles that are
often erroneously called thorns and much of the horticulture effort has
centered on developing prickle-free cultivars.
The final type of berries we pick in
our woods – the mulberry -- grows
on a small tree and is actually of more interest to the wildlife than
us. There are two mulberries in the United States, and ours is the red,
the native species, in contrast to the introduced white mulberry. It
bears great numbers of juicy, dark-red to purple fruits that songbirds
especially enjoy but we find rather tasteless. We found that our collie
Sunny has found them tasty however, as she ate so many she gave herself
indigestion.
As the years have gone by, we have
been content to leave most of the
harvesting of these fruits to the wildlife, but enjoy watching the
various animals, birds and other creatures enjoy them. They make up an
important part of the food chain for many of our residents.
------------------------------------------------------
July 12, 2011:Cougars, and bears,
and wolves, OH, MY!
The Wilson Creek area was somewhat agog this last week after a picture
circulated on the Internet reportedly taken by a game camera belonging
to a local resident. It clearly showed a cougar (also known as puma,
mountain lion, panther, or catamount) with the carcass of a deer in the
background, and seemed to prove that the animal was roaming in our own
backyards.
We have heard tales of this big cat being present in southwestern
Wisconsin as long as we have owned the farm, but this is the first
presumably solid evidence that the stories might be true. Bill and I
knew for a fact the source of one of these instances as we had a hand
in its creation. Years ago, our two collies came home stuck up with
burdocks and full of rotting venison that they promptly threw up on the
living room rug. Determined to avoid a repeat performance, we followed
them up over the hill to a thicket where we found the remains of a
deer. We knew we had to dispose of it in such a way as to prevent the
dogs from continuing their visits and hoisted the carcass up out of
their reach into the lower branches of a nearby tree. Imagine our
surprise and amusement when we heard that it had been discovered by a
hunter who reported that only a cougar could have stashed it there.
The cougar is a large tawny-colored cat with black-tipped ears and long
tail. An adult male may be more than eight feet long nose to tail, and
weigh some 150 pounds while an adult female can be 7 ft long and weigh
about 75 pounds. It can run as fast as 30 mph, jump 20 ft from a
standing position, and vertically leap 8 ft. It prefers to hunt a large
mammal such as a deer but will eat small animals if desperate. It hunts
alone, usually waiting in ambush and killing with a bite at the base of
the skull to break the neck. What cannot be eaten immediately is buried
or partially covered to hide it for a future meal.
Wild cougars probably disappeared from the state by about 1910, but
reports again began to surface in the 1940s of their presence in the
state. Although wildlife biologists felt that these were probably cases
of escaped captives or wrongly identified, it is true that established
cougar populations are found as close as North and South Dakota.
Transient cougars dispersing from these areas have been known to travel
hundreds of miles in search of new territory. Characteristic evidence
of cougars include tracks, which are about three inches long by three
and a half inches wide and typically show no claw marks, or suspicious
kill sites, such as deer carcasses that are largely intact and have
been buried with sticks and debris. Since 1991, the Wisconsin DNR has
conducted a standardized system of collecting reports of cougars and
other rare mammals.
Genetic testing confirmed the presence of two male cougars in December
2009, in northwest Wisconsin. One of these cats had traveled through
the suburbs of the Twin Cities in early December and probably crossed
the frozen river near Stillwater, Minnesota. It was later detected near
Cable in Bayfield County. Another animal was killed in traffic in the
Chicago area after passing through the state. Several other
encounters have occurred in the past two years, the closest being a
probable attack on a young heifer on a farm in the Town of Wonewoc.
Experts tell us that all sightings have been young males, and that
female cougars do not wonder far from their home ranges and are not
likely to set up housekeeping this far East. Still, the reports
continue to occur, and although it was finally revealed that the photo
of the animal in the local e-mails was only posted as a joke, we can’t
discount the possibility that one of these impressive and potentially
dangerous cats will pass through our area.
In fact, what I consider a reliable source reported strange and very
loud roars from an unseen animal across our valley just last
week! Here’s another reason to keep your eyes open!
----------------------------------------------------------
July 6, 2011: Babies and More Babies
Babies are everywhere you look around the farmyard. Bird babies of all
colors and sizes fight over who should get first use of the bathing
facilities at the little pond. Rabbit babies overrun the lawn. Kestrel
babies squawk constantly, complaining they are on the verge of
starvation while making so much noise it must be extremely difficult
for the harried parents to catch a mouse or sparrow that has not been
warned of their presence. Fawns gamble in the hay field. Tadpoles of
all sizes line up along the edges of both ponds, while toads and grey
tree frogs still sing and presumably continue to lay eggs. Caterpillars
are appearing, along with holes in the leaves of all sorts of plants.
Most wild babies have to grow up quickly as the great majority ends up
as meals for other species, and the faster they become proficient at
moving around and caring for themselves, the more likely they are to
survive. Two weeks is a common length of time for the average songbird
to grow from a blind, naked mite to a fully feathered creature capable
of flying about (although most do depend upon their parents to teach
them how to find food for another couple of weeks). Rabbits can care
for themselves by the time they are a few weeks old and a little brown
bat can fly when only 18 days old.
If a species is going to sustain itself, each breeding female must
replace herself with another breeding female before she dies. (The
survival of any one male is less significant as most take many mates
during their lifetimes.) The numbers are amazing. Take American robins
as an instance. In order for robins to continue to arrive each spring
and nest in our apple trees, each pair will have two or sometimes three
broods each year. Each brood contains three to five eggs, so a female
could produce from six to fifteen young each year and therefore up to
thirty babies in the two years she usually lives, and considerably more
should she survive longer. If she and her mate only need to replace
themselves, what happens to all those extra offspring?
A coyote pair has an average of six young each year, although it may be
as few as two and as many as a dozen. They can expect to live 6-8
years, according to the DNR statistics, and if so, will probably have
had at least 30 pups and possibly as many as a hundred.
Consider the cottontail: a female that survives long enough to leave
its nest can expect to live about a year, although some have been known
to live four or five years. She will have three or four litters each
year with three to eight young per litter, although a few up to l0 have
been reported. Therefore, she would probably have had at least 25 young
and possibly many more. Farther south, cottontails may breed year round
with as many as 7 litters a year. We should be overrun!
The female Monarch lays about 400 eggs during her six or eight months
of life, and it has been estimated that our common toad produces close
to 5000 eggs. It is not known how long these amphibians live in the
wild laying long strings of eggs each spring and filling many a puddle
and pond with their tadpoles, but they have been known to subsist for
more than 30 years in captivity.
One of the most prolific breeders of all the mammals is the meadow
vole, a small, common rodent that lives in grassy fields and marshes
and is a close relative of our deer mouse and that pesky house mouse.
It is a short stubby rodent with a rounded face, small eyes, short fur,
and a very short tail. There are 4 species of voles in Wisconsin but
only the meadow vole occurs in any numbers. It lives above ground,
creating little round tunnels in grassy vegetation and eating foliage
and seeds and sometimes tender tree bark, and can cause severe damage,
especially during winter when it is active under the snow.
Females can have 10 litters per year if conditions are favorable, and
if one assumes an average litter contains six offspring, the numbers
are staggering. Voles are born naked and blind but they are fully
furred after 10 days, and reach sexual maturity at 5-7 weeks. The
arithmetic becomes complicated, but if a single female bears litters of
six babies in March and April and her female pups begin their own
litters just two months after birth that would then reach breeding age
in another two months, by the end of the season her total offspring
could top 1000 new rodents.
Some of these various babies are killed in accidents and a fair
percentage are struck down by disease, but the great majority becomes
part of the wild food chain. They are preyed upon by hawks, owls,
foxes, domestic cats and dogs, snakes, crows, herons, shrews, skunks,
bullfrogs, snapping turtles, largemouth bass, and raccoons. Nature can
be cruel to an individual but the goal is survival of each species and
barring major problems, this usually is accomplished and the babies are
certainly cute.
-------------------------------------------
June 28, 2011: Bucky and Friends
We live in The Badger State, display the animal’s picture on our
clothing and other items, and cheer the teams that carry the name, but
chances are that few of us have ever seen one of these creatures in the
wild. They are highly elusive animals, and are most active at night. As
a result, even basic information like how many are still in Wisconsin
and where they can be found is unknown. This knowledge is essential for
badgers' continued survival in the state, as much of their native
habitat has been converted to agriculture.
The badger is a member of the weasel family and is roughly the size of
a large raccoon. The female weighs 15 to 17 lbs whereas a male can
reach 25 lbs or more. It is a distinctive looking animal with long grey
hair, a stout, flattened body, short legs, and a white stripe that runs
down the snout. It has large claws on its strong front limbs that it
uses for digging, and is especially adept at capturing burrowing
mammals such as woodchucks, ground squirrels, and gophers. It will eat
almost anything it can catch, however, and also feeds on voles, mice,
ground-nesting birds, insects, and carrion, providing an important
service in helping to control rodents and other agricultural pests.
Badgers are solitary animals and despite their "waddle-like" walk, most
hunt over large home ranges that vary in size depending on the
availability of prey. Kits are born in the spring and remain with their
mother until late summer at which time they strike out on their own --
sometimes traveling long distances from their mother's range. This is a
very dangerous time as many are killed while attempting to cross roads
and railroads.
Annual badger hunts in Wisconsin used to harvest up to 4600 animals.
The average price for a pelt was $1.95 and the fur was used for
clothing as well as shaving brushes. The take eventually began to drop,
however, and only 128 animals were shot or trapped in Wisconsin in
1954, with an average pelt value of only 29 cents.
In 1957, the badger became Wisconsin's official state animal, suggested
by the nickname given to some of Wisconsin's earliest European
settlers, Cornish and Welsh miners who spent much of their time
tunneling in the dirt like badgers. Also, the University of
Wisconsin-Madison, adopted Buckingham U. Badger ("Bucky") as their
mascot. Badgers had a reputation for being fearsome and tenacious, two
characteristics that made them popular as mascots for the teams. At the
same time they were given protected status and all hunting and trapping
was halted.
Emily Latch, a recently arrived assistant biology professor at the
University of Wisconsin-Milwaukee thought it strange that there was no
current research being carried on about the badger when the state used
the animal as its mascot, and decided to do something about it. She
suggested that little study had been done on the badger because it was
neither endangered nor a game animal in Wisconsin. Plus, it was
difficult to find.
"They're nocturnal, they're mean, they're underground, they're solitary
- all of which makes them difficult for research," said Latch. "I
didn't want the badger to fall into the situation where you've got
Bucky Badger but no badgers". So she and a graduate student recently
started the Wisconsin Badger Genetics Project to learn more about these
secretive, nocturnal, digging machines whose preferred grassland
habitat has been increasingly lost.
With funding from the Department of Natural Resources, they recently
set up a web site - <badgerresearch.uwm.edu> - and printed fliers
to get the word out. They hope to collect DNA samples from as many
badgers as they can through both road-kill and live animals. Once they
learn more about their population and distribution, they hope to
correlate information with habitat and perhaps reintroduce animals to
promising areas where they have been eliminated.
As part of the project, they hope to set up video and trail cameras,
using tracking stations that capture claw prints, and perhaps even
affix radio transmitters to some of the animals. Except for nursing
mothers, badgers typically stay in a burrow for only a few days before
moving on and digging another den. The researchers are encouraging
people who see burrows, especially active ones, to contact them so they
can set up hair snares (designed to grab a few hairs without hurting
the animals) in an attempt to obtain DNA. At this point, they
report
that they have obtained five samples from each of Dane, Iowa, and
Columbia Countries, but only one in Sauk and none in Richland County.
Collecting the genetic signature of as many different animals as
possible is the primary goal and they hope to begin to estimate
population numbers, movement patterns, and even territory sizes. We are
asked to help in this study so keep your eyes open for burrows and be
sure to report any activity you see.
-------------------------------------------------
June 21, 2011: Silk a Miracle Fiber
Drive along a country road after a
foggy night and you will probably
see hundreds of spider webs, made unusually visible by the dew droplets
caught on their strands. One common variety is spun by the bowl and
doily spider, a tiny arachnid only about a quarter inch long, that
weaves a fairly complex structure consisting of an inverted dome shaped
web, or "bowl", suspended above a horizontal sheet web, or "doily".
Other sheet web types include the
classic cobweb – a messy, irregular
but quite effective trap with sticky outer threads, and the funnel web
that includes a hideaway that houses the spider. It feels vibrations of
an intruder, rushes out and bites it, and carries it back into the
funnel. The orb web spider, in contrast, constructs a rectangle-like
frame of silk and then adds numerous rays of sticky silk radiating from
the center to the frame with spirals of silk laid down over all.
Spider silk is a remarkably strong
material with tensile strength
comparable to that of high-grade steel, although it has only about a
fifth its density and a strand long enough to circle the Earth would
weigh less than 18 ounces. All spiders produce silk and can make up to
seven types. By winding the varieties together in varying proportions,
spiders can form a wide range of fiber material for different uses.
These include constructing a web to capture prey, as well as wrapping
up paralyzed creatures for future use. Some enclose their eggs in silk
sacs that protect them until they hatch, and others line their nests
with the fibers. Newly hatched spiderlings often extrude several
threads into the air and let themselves be carried away by upward
breezes to populate new areas.
Spiders have special glands that
secrete the silk proteins, which are
made up of chains of amino acids dissolved in a water-based solution.
The spider pushes the liquid solution through long ducts, leading to
microscopic spigots on the spider's spinnerets, typically located at
the rear of the abdomen. These wind the strands together to form the
sturdy silk fiber. New information just released is also thought to
prove that some tarantulas can produce silk from glands on their feet
that seem to help them negotiate slippery inclines.
The best-known type of silk, however,
is not that of spiders, but is
found in the cocoons of the larvae of the mulberry silkworm – an insect
that no longer lives in the wild and is completely domesticated. Its
larva makes silk in its salivary glands and has a spinneret on its
lower lip from which it draws the fiber. The shimmering appearance of
silk is due to its triangular prism-like structure, which allows silk
cloth to refract incoming light at different angles, thus producing
different colors.
There are five major types of silk of
commercial importance, obtained
from different species of silkworms: these are Mulberry silk that
constitutes the bulk of world silk production; Tasar silk produced by
another species of silkworm which is reared outdoors on Asan and Arjun
trees; Oak Tasar, a finer variety produced in both India and China by
two different varieties of silkworm; Eri, a silk spun from open-ended
cocoons unlike other varieties of silk, and created by a domesticated
silkworm which feeds mainly on castor leaves; and Muga, a golden yellow
color silk that is exclusive to India and is obtained from a
semi-domesticated silkworm that feeds on the aromatic leaves of Som and
Soalu plants.
While spiders and the larvae of many
moths and butterflies are well
known producers of silk, they are not the only invertebrates that use
it. Dr Tara Sutherland and her Entomology group from The Commonwealth
Scientific and Industrial Research Organization in Australia are
looking at silks produced by other insects. “Most people are
unaware that bees and ants produce silk, but they do and its molecular
structure is very different from that of the structure of moth and
spider silk. The cocoon and nest silks we looked at consist of coiled
coils - a protein structural arrangement where multiple helices wind
around each other. This structure produces a light weight, very tough
silk,” she says. Honeybee larvae produce silk to reinforce the wax
cells in which they pupate, some ant larvae spin solitary cocoons for
protection during pupation, bumblebee larvae spin cocoons within wax
hives, and weaver ants use their larvae as ‘tools’ to fasten fresh
plant leaves together to form large communal nests.
The first successful man-made silks
were developed in the 1890s of
cellulose fiber and marketed as art silk or viscose, a name officially
changed to rayon in the 1920s. Nylon, the first synthetic fiber, was
developed in the late 1930s and used as a replacement for Japanese silk
during World War II. Its properties are far superior to rayon and silk
when wet, and so it was used for many military applications, such as
parachutes. In the present day, imitation silk may be made with rayon,
mercerized cotton, polyester, or a blend of these materials: still,
despite a generally similar appearance, genuine silk has unique
features that have never been duplicated. We still have much to learn
from Mother Nature.
--------------------------------------------------
June 14, 2011: Weeds,
Weeds, and More Weeds!
This is a Year of the Weed. If you are
gardener or just enjoy looking
at cultivated areas, you probably have noticed that undesirable plants
have been growing with a bit more enthusiasm than usual and we have had
to work harder to hold them in check. I suspect this has been true
because this spring’s cool temperatures and abundant rainfall has
favored them over more delicate plantings and they took over before we
realized it.
A weed in a general sense is a plant
that is considered to be a
nuisance, and the name has normally applied to unwanted plants in farm
fields and gardens, but also lawns, parks, and woods. More
specifically, the term describes plants that grow and reproduce
aggressively to the detriment of more desirable growth. Weeds may be
unsightly, or crowd out or restrict light to other plants or use up
limited nutrients from the soil. Some weeds have thorns or prickles,
while others have chemicals that cause skin irritation or are hazardous
if eaten, or have parts that come off and attach to fur or clothes.
The State of Wisconsin has named some
75 plants to be considered
invasive or noxious weeds. Some twelve of these are trees, and include
Norway maple, Chinese elm, and white poplar. Another dozen or so are
shrubs such as Japanese barberry, honeysuckle, Russian olive, and
euonymus. A few are grasses including reed canary grass, quack, and
even Kentucky bluegrass. Some so called weeds are even considered
desirable by some and have been sold and planted deliberately --
periwinkle, crown vetch, multiflora rose, forget-me-nots, purple
loosestrife, dame’s rocket, and orange daylily, among others.
A new invasive species rule, Chapter
NR 40, took effect September 1,
2009, that aims to keep out new invaders and allows the DNR to move
more rapidly to prevent them from getting established when they're
detected. So many different non-native species have been documented on
land and in water that you might think there is no hope that invasives
can be contained or controlled, but that is not the case for all
species. A team of DNR staff specialists and the Wisconsin Council on
Invasive Species working with an advisory group identified over 120
species as being invasive and grouped them as plants, fish and
crayfish, other vertebrates and invertebrates and plant disease causing
microorganisms. Each organism was classified as either prohibited or
restricted, warranting different actions.
Prohibited species are those that are
not yet known to be established
in Wisconsin that would likely cause serious problems if left
unchecked. As a prevention strategy, no person may transport, possess,
transfer or introduce any of these species without a permit and when a
prohibited species is discovered, the goal is to eradicate it if
feasible or at least prevent it from spreading. Wisconsin DNR staff
will work with the landowner to determine the best method of control,
and where possible, will seek to find funding, equipment, volunteers or
other assistance to help with the control.
Restricted species are usually fairly
widespread throughout the region
and the chance of statewide eradication is low. Many of these species
have already caused substantial economic and environmental damage and
some are known to harm human health. If a restricted species is present
on your property, control is encouraged but is not required. Some
plant species are listed in both categories – restricted where the
species is already established and prohibited in large portions of the
state where it has not been found.
The Wisconsin Department of Natural
Resources has received a federal
grant of nearly $806,000 to pay for herbicide spraying of an invasive
aggressive weed starting this August. Phragmites, also called the
common reed, is a large perennial grass found in wetlands throughout
temperate and tropical regions of the world and is found on the shores
of Lake Michigan and the Bay of Green Bay. In North America, it was
commonly considered an exotic and often invasive species introduced
from Europe, although there is evidence that one variety was present
long before Europeans arrived on the continent. Phragmites can grow up
to 20 feet tall and commonly forms extensive stands which may be as
much as 1/3 mile across, spreading 16 feet or more each year by
horizontal runners. It likes damp ground but can grow in standing water
up to 3 feet deep, or even as a floating mat, crowding out native
species and obscuring waterfront views.
The Nature Conservancy suggests
several guidelines to help slow the
introduction and spread of invasive species. Know what plants you have
in your yard and on land over which you have some control and be sure
any plants you introduce are not invasive. Clean your shoes before you
hike in a new area to get rid of hitchhiking weed seeds. (This is
especially important in areas infested with garlic mustard.) Don’t move
firewood that might harbor forest pests. When boating, clean your boat
thoroughly before transporting it to a different body of water and
don't release aquarium fish or plants, or live bait into the wild. We
can prevent more than forest fires...
------------------------------------------------
June 8, 2011: Gnats:
Pesky Critters
One of the irritations that we sometimes encounter at this time of year
is walking into a large swarm of tiny insects or perhaps sitting on the
porch and finding ourselves engulfed. They buzz around one’s head, and
often seem to be particularly attracted to the eyes and nose. They are
sometimes called gnats, flies, midges and no-see-ums, and contrary to
popular belief, these tiny flying insects are not "babies", but adults.
Just what are these pesky critters?
Gnat is the common name for any of the small, winged insects in the fly
family. The presence of a single pair of wings distinguishes true flies
from other insects with "fly" in their name, such as mayflies,
dragonflies, damselflies, and butterflies, and it is a huge order,
containing an estimated 240,000 species, including mosquitoes, gnats,
and midges. They are attracted to the carbon dioxide in your breath
because the rotten fruits and stuff upon which they depend for food
also emit CO2 vapors and they are investigating to see if you are good
to eat. Body odors such as sweat and lactic acid, combined with heat,
are also enticing agents, and any moisture, whether on the body or in
standing water, attract them as potential breeding grounds or sources
of blood.
Adult gnats range in size from one to three millimeters, depending upon
the species, and can be separated into several general types. Black
gnats are seldom truly black and there are over 1,000 species
worldwide. They lay their eggs in all types of moving water and their
larvae spend about ten days clinging to rocks and water plants before
emerging as adults. These prefer to feed on flower nectar, but females
also feed on blood and will bite humans. They often move about in large
swarms and although they are most active in the morning, they are more
apt to bite as nightfall approaches. These flies also have been known
to spread disease and have caused river blindness in Africa and parts
of North America.
Biting midges (including what are called no-see-ums, sand flies, and
punkies) are a group that is closely related to black flies. They are
found in almost any aquatic habitat throughout the world and the
females of most species are adapted to suck blood from some kind of
host animal. Larvae are always found in damp locations such as under
bark, in rotten wood, compost, mud, stream margins, tree holes, or
water-holding plants. The smaller members of the family are tiny enough
to pass through typical window screens, and camping tents are often
equipped with extra-fine mesh netting to keep the pests out. Many
of the blood-eating species are found in beach or mountain habitats and
may be carriers of disease-causing viruses, protozoa, and filarial
worms. In humans, their bites can cause itchy, red welts that can
persist for more than a week, the discomfort arising from an allergic
reaction to the proteins in their saliva.
House gnat is the name many people use for small flying insects they
see in their homes. Most commonly encountered is the fruit fly that can
often be found hovering near food in the kitchen. Many of these are
brought in with the fruits and vegetables from stores, but some also
can come in from the garden. These can be any of the hundreds of
species but fall into two general categories – larger, colorfully
marked insects or a smaller type that includes the important species
that are used in modern research. Also sometimes found in the
home are fungus gnats that thrive in the damp soil of over-watered
houseplants. Their larvae feed on decomposing organic matter in the
pots, and if the population is large, the plant's roots and root system
will be in danger. They are most harmful to small plants and large
healthy plants are less likely to be damaged.
Frit or grass flies are usually yellow or black and appear shiny due to
the lack of any hairs. The majority of their larvae feed on plants,
mainly on grasses, and can be major pests of grains. A few species will
feed on eye secretions such as tears and other body fluids, and are
particularly bothersome around one’s face.
Gall gnats are very fragile small insects characterized by long
antennae and hairy wings, unusual among the flies. Their larvae damage
plants by producing chemicals that cause the host plants to form
abnormal swellings that both protect and feed the growing grubs. Many
are economically significant such as the important insect pest of
wheat, the Hessian fly, whose galls can cause severe damage to the
crop. Other important pests include the lentil flower midge and the
alfalfa sprout midge on legumes, the raspberry cane midge on fruit
crops; and the rosette gall midge on goldenrod stalks.
Husband Bill contends that two simple procedures are effective in
thwarting any of gnats that attempt to harass you: breathe forcefully
off to the side to divert their aim on your CO2, and wave a black
cherry leafy twig in front of your face. Good luck...
----------------------------------------------
May 30, 2011: Nests of all Kinds
When I passed the open machine shed in
the farmyard, a female robin
squawked and practically collided with me as she flew out in a rush. It
was obvious that she had tucked a nest onto one of the shed beams and
there it was at eye level in plain sight.
The female robin builds a cup nest of
mud, sticks and grasses in a
protected area on a firm support. It can be anywhere from ground to
treetop in height but the site must be on something sturdy enough to
anchor the nest securely in place and where it would be protected from
sun, wind and rain. It should also be very close to a good feeding area
and not too far from water.
It takes a female robin untold numbers
of trips to gather materials to
build the nest. She begins by collecting mouthfuls of mud in her beak
after a soaking rain and laying a foundation. Then she gathers several
hundred tiny twigs and dead grass blades and uses her bill and feet to
weave them together, cementing them to each other and to the support
with mud. After each addition, the female climbs into the growing
structure and uses her body to compress the mud, smoothing and shaping
it with her breast. The nest must be tight and snug enough to cradle
the eggs and hold in warmth, but large enough to hold four or even five
growing nestlings.
Other bird nests vary from a simple
accumulation of materials on the
ground to elaborate refuges in secluded sites. Scrape nests are simple
depressions in the ground -- sometimes with a few stones or twigs added
-- or in the leaf litter. Such nests are used by ruffed grouse,
pheasants, quail, nighthawks, vultures, many ducks, and most
shorebirds. Bank swallows and belted kingfishers burrow right into the
ground to create nests that are very effective at protecting eggs and
young from predators and most bad weather.
Cavity nests are also used by
woodpeckers, owls, wood ducks, and some
songbirds but these holes are not in the earth but in trees.
Woodpeckers use their strong beaks to create hollows in living and dead
tree trunks and branches, and the other birds take over the holes for
their own use when the woodpeckers abandon them.
Bald eagles, that use substantial
sticks as much as two inches thick
and several feet long, make sturdy and long lasting platform nests.
They may look like a jumble of materials, but the sticks are usually
placed in layers, beginning with a triangle, followed by more rotated,
triangular layers. Hawks, geese, cranes, and herons also build
relatively flat nests--some located on the ground, in trees, or on the
tops of rooted vegetation or debris in shallow water.
The most complex constructions are
associated with orioles that build
intricately woven pendant nests. The female chooses a tall tree that
has hanging branches and winds a long animal hair or plant fiber around
a strong twig. She adds another fiber winding it around the first and
the twig, and keeps adding and weaving material until she has a tangled
mass hanging from three or four anchors. This will become one side of
the nest. The female then starts weaving in fibers and twigs to form
the nest's skeleton, and weaves in more fibers to fill it out. As it
starts to get round, she sits inside and pushes and presses on the
bottom and sides to shape it until it feels secure.
Many of these more complex nests
require days and even weeks of work,
but after one use, most nests are abandoned. Even the cleanest bird
family can't keep mites, lice and flies out, and once they get started,
they can really multiply fast, making an old nest unsafe for a new
batch of babies. At least 2500 species of mites from 40 families are
closely associated with birds, occupying all conceivable habitats in
the nests and on the bodies of their hosts, and no birds are free from
a mite associate. These mites have short generation times and can
rapidly build up huge populations. Blood-feeding nest mites can slow
development or even kill chicks.
Our family had some experience with
bird mites while staying over-night
in a cabin some years ago. Only a thin wall separated a recently
occupied phoebe nest outside under the eaves from where our young sons
were sleeping in upper bunks. The hungry mites promptly moved indoors
and by morning, the boys were covered with bites.
It is believed that nest building is
primarily instinctive, as birds
tend to build nests that are very similar to others of their species,
regardless of where they are located. In addition, captive birds raised
by themselves also build similar nests proving that they were not
learning techniques from example. That said, some learning is also
involved because older birds usually build 'better' nests than young
birds that are making their first attempt. Some also seem to like
special adornments, and candy wrappers, cellophane, shredded money –
even barbed wire – have shown up in nests. Keep your eyes open and see
how many different types you can discover.
------------------------------------------------
May 24, 2011: The Amazing
Ruby Throat
You have to be impressed with a
ruby-throated hummingbird: it is only
about three and a half inches from its beak to the tip of its tail and
weighs only about 1/8th ounce; its body temperature is at least
105ºF and it breathes 250 times a minute at rest and 1200 times
when flying; its wings beat an average of about 50 times each second
and it normally flies at about 30 mph but may go as fast as 60 mph when
diving; and most live three or four years, a surprisingly long life for
such a tiny creature with a long and difficult migration.
Probably the most intriguing fact for
many scientists (as well as us
amateurs) is the fact that the hummingbird flies to Mexico or Central
America each fall and then returns to the same feeders or gardens to
breed year after year. What's more, according to professional banders
working for many years, they often stop at the same spots along the way
and arrive on the same date! How do they do that?
There doesn’t seem to be any one
answer. Young, inexperienced birds
appear to have an inborn ability to travel in a particular direction
for a specified time and distance on their first migration, but on the
return journey and forever afterwards they seem to use a variety of
cues to guide them back to the area from which they came.
Available evidence clearly indicates
that most birds have a number of
‘compasses’ that can be used for orientation and determining their
location. Thus, many birds can determine where they are and then select
a course or direction that will take them to their goal. They can
potentially choose from several compass mechanisms, including magnetic
cues as well as the location and movement of the sun and stars.
Many birds have iron oxide particles
in certain neurons in their heads,
primarily in the upper beak. Electrophysiological recordings from
associated nerves and the results of several behavioral studies
indicate that these iron-based receptors provide birds with information
about magnetic field intensity and direction. The earth’s magnetic
field, caused by electrical current generated by its rotating molten
core, is slightly tilted relative to the spin axis so the two poles
(magnetic north and south) are located several hundred kilometers from
the geographic poles. Field lines leave the earth at the southern
magnetic pole, curve around, and then re-enter the earth and the
northern magnetic pole.
The compasses we use simply point to
magnetic poles. In contrast, the
avian magnetic compass is an inclination compass; that is, birds use
the inclination of magnetic field lines relative to the earth’s
surface. It is thought that the magnetic field may be translated into a
visual pattern transmitted to the brain from the retina allowing the
bird to determine its direction of movement relative to a magnetic pole
and the magnetic equator.
Day-migrating birds use the sun's
position in the sky -- and where it
is at different times of day -- to stay on course. (Scientists think
the pineal gland on the tops of birds' brains is sensitive to light.)
Birds using the sun for orientation must compensate for the sun’s
movement, a task made more difficult by variation in the speed of
movement during the day. In addition, the rate of change in the sun’s
azimuth varies with latitude and season. Despite this apparent
complexity, birds that use the sun compass appear to have a precise
understanding of how the sun’s azimuth changes.
Star-compass orientation has also been
demonstrated in several species
of night-migrating songbirds, but it has been determined that birds
that use stellar cues for orientation must learn to use this ‘compass’
by observation. Experiments have also revealed that birds do not rely
on specific stars like the North Star, but from the position of stars
and constellations relative to each other and to the celestial pole.
When nearing its goal, a bird likely
uses finer landscape features such
as general topography, patterns generated by areas or patches of
different habitat types, bodies of water, and, in some areas, man-made
features such as roads and tall buildings. Finally, birds likely use
specific features or landmarks in their breeding territory or wintering
area, to determine that they have arrived at the desired destination.
Some scientists wonder whether birds even use their senses of smell and
hearing to locate familiar places.
All of this innate programming and
learned information in a hummingbird
takes place in a brain about the size of a grain of rice, and if that
doesn’t make you shake your head in bewilderment, nothing will. Mother
Nature continues to amaze and tantalize us with the wonders of her
creation.
--------------------------------------
May 17, 2011: Flowering Trees
While daffodils, tulips, and the
wildflowers such as trillium and
anemones are highly prized in our gardens, the plants that really draw
our attention at this time are the flowering trees. Few sights can
rival a magnolia or apple tree in full bloom, but the fact is every
tree flowers in the spring, even before the leaves appear.
Blossoms are the reproductive
structures whose function is to allow
sperm to unite with eggs in plants. They come in a bewildering variety
of shapes and sizes, but all must have at least one of four basic
parts. The typical flower has both male and female structures. The
basic unit of the male organ is known as the stamen, and there may be
any number of these usually radiating out from the blossom's center.
When the stamen is sexually mature, an organ on its tip splits open and
yellow, dust-like pollen emerges carrying within them the plant's male
sex cells. The female structure is found in the center of the blossom
and contains an ovary that produces egg cells. It possesses a sticky
tip that collects the pollen and becomes the pathway for pollen tubes
which direct the male cells to the ovary.
Before a typical flower opens, it is
folded neatly inside a small tight
bud that protects it from insects, temperature extremes, sunlight, and
other things. When conditions are favorable, the tough covering splits
and spreads into segments called sepals, and as the blossom continues
to enlarge, this structure remains at its base. (Some flowers have no
sepals at all but others may be quite prominent and petal-like.) Inside
the sepals are usually found the petals, typically five. These are
almost always thin, soft and brightly colored to attract creatures that
help pollination. Inside the whorl or whorls of petals are the stamens
and inside those are the ovaries that produce the egg cells and
ultimately the seeds.
Flowering crab, apple and magnolia
trees have what are called perfect
flowers—that is, they possess all four basic structures displayed
prominently for all to see. These can pollinate themselves, but
many of our other trees have what have been designated as imperfect
flowers. Each contains only one set of reproductive organs, so they are
either male or female and it takes both types to create seeds.
Imperfect flowers may be pollinated by animals, insects, weather or
humans, but they will always need some sort of outside help in order to
transfer the pollen.
Oak trees flower in two stages: first
comes the production of the male
flowers on long slender stalks called catkins that emerge from mixed
buds at the ends of the branches; second are the female flowers, which
are located at the base of a leaf node on a new branch or twig. The
timing of the two stages is staggered on any given tree to prevent
self-pollination. The male flowers have no petals and so are
relatively inconspicuous but they contain pollen sacks that swell and
release the pollen into the wind. The wind carries the pollen to
neighboring trees that have already opened their female flowers.
Catkins form on the trees in late
summer, remaining tight, smooth, and
closed throughout the winter. They begin to expand in early spring,
with most flowering before the leaves appear, or at least before the
leaves get too large. As catkins rely on wind to spread their pollen,
this arrangement prevents the leaves from interfering with
fertilization. Other trees with catkins include willows, aspens,
poplars, birches, alders, mulberries, walnuts, and hickories. In the
Willow family, both male and female flowers occur in the form of
catkins, and usually a given tree is either male or female. Some
species such as pussy willows start out with a silvery fuzz, followed
by stamens with yellow, pollen-bearing heads.
American elm is one of the first trees
to come into flower, and has
perfect, creamy-brown to greenish red flowers. The blossoms do not have
petals, but are noticeable because they sway on drooping stalks when
most other trees still stand bare and seemingly lifeless. Maple flowers
are also very early and may be green, yellow, orange or red, depending
upon the species. Though individually small, the effect of an entire
tree in flower can be striking and they are a welcome source of pollen
and nectar for bees.
Aspens have drooping male catkins but
many other male catkins are small
and upright. Birches also have small, upright female catkins but the
female flowers of most of the various species take other forms, usually
smaller and round, and these develop later in the year into acorns,
alder cones, hickory nuts, walnuts, and other fruits. Walnuts,
hickories, and oaks flower a bit later and after the female flowers are
fertilized, the male catkins wither and drop.
It is tempting to just smell the wild
plum blossoms along the road and
to feast your eyes on the flowering crab trees in the village, but also
take time to look for all the other flowers on the trees in our yards,
woodlots and forests.
------------------------------------------------------
May 5, 2011: A Walk in the Woods
One of the most spectacular songbirds
that spend the summer with us is
the rose-breasted grosbeak. It belongs to the cardinal family and has
the same large beak – hence that part of its name. Adult birds are
about seven inches long and the male has a jet-black head, wings, back
and tail, white patches on its wings and underparts, and a bright
rose-red patch on its breast. The adult female has dark grey-brown
upperparts and looks much like a large sparrow except for its outsized
beak, and is nearly twice the weight of its mate.
We have had several males visiting the
one basket feeder we are still
maintaining, and have enjoyed their relatively friendly ways and
certainly their showy plumage. It was with dismay, therefore,
when—right before our eyes—one was snatched off the basket and borne to
the ground in a flurry of feathers. A female sharp-shinned hawk not
much bigger than the grosbeak had seen the activity in the old apple
tree, and helped itself to an easy meal.
The sharp-shinned is the smallest hawk
to reside in the United States
and Canada and has become a regular visitor to bird feeders, where it
eats the birds, not the seed. These days, fewer of the hawks may even
be migrating south, preferring instead to stay farther north where they
have found a dependable winter food source at feeders.
Sharpies typically nest in forests,
preferably those with conifers, and
place a substantial platform of large conifer twigs on a horizontal
limb high in a dense tree. Both males and females engage in territorial
displays in which the birds fly with stiff, slow wing beats while
exposing white under their tails, and giving their "kik-kik-kik" call.
They capture birds by quietly sneaking up on them and then pouncing, or
after a short chase.
We have been pleased to greet other
old avian friends, as well. A male
hummingbird showed up last Wednesday at the nectar feeder on the patio
door, making us glad that we had made up a supply of syrup and put it
out. According to a website where watchers post their sightings, the
first hummer was spotted along the Gulf coast the end of February, and
one was seen in this area the middle of April, so I shouldn’t have been
surprised. Still, it is hard to imagine the distances that tiny bird
traveled since it left us last fall and we are glad to see it back.
The nectar feeder in the front yard
has also attracted a pair of
northern orioles this week. I don’t know how these birds manage to
extract syrup from the small holes in the feeder, but presumably their
tongues are long enough to reach it. I should put out some jelly, as it
would be easier for them to get. A wren has also been singing
several places around the farmyard, checking out the houses Bill
cleaned out for him to inspect, and claiming them with a few twigs.
Robins are already nesting in the sheds and we have picked up broken
bits of blue eggshells so I assume there are babies in some of the
nurseries. We have even seen barn swallows skimming the fields near the
house for flying insects, and one guest reported seeing an indigo
bunting—often the last migrant to appear each spring.
Much as we enjoy watching the birds
return, the wildflowers command an
equal amount of our attention, and a constant procession of blossoms
keeps us revisiting each trail every few days to avoid missing any of
them. The bloodroot, Dutchman’s britches and hepatica blossoms are
almost gone, although the leaves are still growing larger and their
seeds are yet to come; the anemones, bellwort, violets, and Virginia
bluebells are in full bloom; and just emerging are the blue wood phlox,
shooting stars, columbine, and may apples.
The star of our wild garden show is
the yellow ladyslipper, with the
showy orchis a close second. We always replant at least half of the
ladyslippers we dig for the sale so that now there are some hundred
plants just in our wild garden as well as many more out around the
farm. The golden pouches shine in the sun when fully developed and each
year more appear as the plants divide and maybe even seed. Although
these wild orchids have no federal protection, Wisconsin lists them as
plants of special concern, and we are pleased to see their numbers
increase on our farm as well as to distribute a few each year to others.
The showy orchis is a much smaller
member of the orchid family that s
occurs in small clusters. Each plant has a 6-8 inch stalk rising
between two flat, glossy leaves and displaying up to a dozen flowers,
each of which consists of a pink hood over a white, spurred lip petal.
This was the first wild flower I found when I cleared the area for my
wild garden and so is especially treasured.
May your springtime be blessed with
warm breezes, bright sunshine mixed
with sufficient showers, singing birds, myriads of fragrant colorful
flowers, and the will to see, hear, smell, and feel the wonders that
surround us.
----------------------------------------------------
May 3, 2011:
A Walk in the Woods
The last couple of weeks, we have been
spending long delightful hours
in the wild garden preparing for our open houses and marveling at the
richness and variety of plants that flourish there. The plot was
originally the grape arbor of the old bachelor who owned the farm, and
after he died the neglected vines spread across the ground sheltering a
sparse collection of miscellaneous odds and ends.
When we first explored the area, there
was little but a couple dozen
spindly aspen, hickory, and elms growing on mostly bare ground. Still,
it was close to the farmyard and the discovery of several showy orchis
plants hiding among the weeds led us to guess that it might be a
potential spot for a wild garden. We thinned out the remaining grape
vines and cut a number of the unwanted trees.
We laid out paths and covered them
with sawdust, collected plants from
other spots on the farm where they grew in profusion, and bought in
others that were native to Southwest Wisconsin. Each year since, their
numbers have increased and now each spring is a treasure hunt to find
the seedlings that have spread throughout the area. The various parts
of our natural woods tend to produce just a few species in any one
spot, making one wonder if the conditions are special in each
particular location, but here, the plants all thrive together. Whatever
the reason, the results are worth getting out and seeing, and if you
didn't make it last week, we hope you will visit this Saturday or
Sunday.
A wild garden is home to far more
things than wildflowers, but whether
creatures make their presence known depends upon their shyness, the
time of day or sometimes the weather. Warm sun brings butterflies and
bees to visit the blossoms of the prairie flowers; birds are
enthusiastically establishing their territories and pairing up
regardless of the weather; and the snakes are emerging from their
winter shelters. Warm evenings bring out the moths, singing tree frogs
and toads, mice and other burrowing rodents, and sometimes the larger
animals like raccoons and possums.
Many of the migrant birds have not yet
arrived, but the chipping and
song sparrows, as well as the phoebes, are here and busily setting up
housekeeping. The chipper is a small gray-breasted sparrow with a
bright rufous cap and a black line through its eye. Its chicks develop
at an amazing rate. Each starts as a blind, naked mite weighting less
than 2 grams, and 14 days later it is fully feathered and flying. The
song sparrow is larger than the chipper and can be identified by its
song as well as its streaked breast with a prominent blotchy spot at
the center.
The Eastern phoebe, a flycatcher, also
arrives early for one who
depends upon flying insects for food, and I would think that they must
go hungry on many of these cold spring days. All of the flycatchers
have wide, flat bills that have hairy bristles at the base, presumably
to help them funnel insects into their mouths, and they fly out from a
perch to snatch prey in mid-flight. We have several pairs that nest
around the farm buildings, and a favorite usually builds under the
eaves of the little stone building we use as headquarters for our plant
sales. For many years the female used a site directly over the doorway
but she has since moved around to the back of the building, no doubt
considering the human traffic too intrusive.
We often have spied an occasional
tiger swallowtail butterfly along
with the painted ladies, cabbage, blues, and tortoise shells that
usually appear on warmish days in April. The tiger has distinctive
yellow and black striped markings and usually has a wingspan of four or
five inches. An interesting fact about its development is that its
mature caterpillar has markings that resemble large yellow eyes with
black pupils on its green body, and when it wraps itself in a leaf,
looks remarkably like a snake. This year with its slow warm-up, all the
butterflies are scarce.
It is hard to miss the activities of
the amphibians. The spring peeper
is a woodland tree frog that must find semi-permanent water in which to
lay its eggs. The male makes a distinctive peeping much like that of a
baby chick and a large chorus can be ear splitting. We almost never see
a peeper during the rest of the year as they do most of their hunting
and moving about after dark, but they appear by the dozen at our ponds
in April. Another tree frog, the eastern gray, is about 2 ½
inches long and may be any color from bright green to gray, depending
upon its surroundings, its temperature, and its activities. If you can
catch one, you would find that the insides of its thighs and legs are
always bright orange and that it has large toe pads that allow it to
climb on any surface, even glass windows.
We enjoyed seeing so many of you last
weekend at our first open house
and hope the weather will be more amiable this coming weekend. There
are still many dozen varieties of potted native plants for sale, and
you are welcome to just come and enjoy a spring day in the Wisconsin
outdoors. You could also bring your mother to view the wild
garden or buy a plant for her for Mother’s Day.
April 26, 2011: Courting Birds
Most people consider bluebirds to be
their favorite songbirds, and so
are usually willing to forgive almost any strange behavior they might
exhibit. I was surprised then to have neighbors across the hill
expressing somewhat negative feelings about them. It seems that a pair
has claimed a bluebird house near their barn and are now showing their
displeasure on any vehicles parked in the vicinity. Evidently they
mistake their own images in any reflective surfaces—particularly the
side mirrors on the family cars—for competing bluebirds, and not only
attack them repeatedly, but deposit their droppings in such a way as to
completely cover the surfaces.
Bluebirds are not the only birds to
cause problems in the springtime.
Woodpeckers are notorious for hammering on wooden shingles, cedar or
redwood siding, and metal or plastic gutters, particularly those
materials that produce loud hollow sounds. Unlike most other birds,
woodpeckers do not sing and so advertise their territories and attract
mates by drumming. The exact pattern of the drumming will vary in
tempo, length and rhythm depending on the woodpecker species, and they
have special physical adaptations that allow them to peck quickly and
repeatedly on hard objects without hurting themselves. Thicker skulls
cushion the birds' brains and heads from hard impacts, and strong neck
muscles allow them to drum for long periods of time without strain.
Their bills are also thick, straight and sturdy to withstand drumming
impacts.
Every species of bird performs its
courtship in a slightly different
manner. These differences help to ensure that only birds of the same
species will mate, and that each bird is attracted to a member of the
opposite sex. Before mating season, many male birds grow colorful
plumage that they show off in various ways. Others that are less
colorful often use complicated and individual songs to identify
themselves and to attract a mate. Depending on the type of behavior,
how the birds react in courtship can also display strength, health and
mating desirability, allowing different birds to choose the best
partners and ensure viable offspring.
Singing is one of the common ways
birds try to attract a mate and songs
vary in complexity or variety. Singing can also advertise the
boundaries of one bird’s territory and warn off competitors. For some
species, only the males will sing, while for other species the pair may
duet as part of the bonding ritual.
Bright plumage colors and elaborate
displays of prominent feathers,
skin sacs or body shape can show off how strong and healthy a bird is,
advertising its suitability as a mate. Peafowl are one of the
best-known bird species for their stunning display with the males’
extensive fans, though other birds may use subtle changes in posture to
show off their plumage just as enthusiastically.
Physical movements, from daring dives
to intricate behaviors including
wing flaps, head dips, or different steps can be part of a courtship
ritual. In many species, the male alone will dance or perform
aerobatics for his female while she observes his actions, while in
other species both partners will interact with one another. Dance
mistakes evidently show inexperience or hesitancy and the pair often
fair to mate.
The birds may lightly preen one
another, sit with their bodies touching
or otherwise lean on one another. Offering food is another common act
of the bird courtship behavior for many species. Typically a male bird
may bring a morsel to the female, presumably demonstrating that he is
able not only to find food, but that he will share it and is able to
provide for her while she incubates eggs or tends the brood.
Some birds even seek to attract a mate
by showing off their
architectural skills. Constructing nests before the female arrives is a
way for males to claim territory and show the suitable nesting areas
they can defend. They may also decorate the nest with pebbles, moss,
flowers or even litter to make it more eye-catching. The female may
then choose the nest she prefers, or she may still build her own after
mating with her chosen male.
It is an interesting springtime
activity to observe their varying
courtships going on all around us, but discouraging persistent courting
birds can be a challenge for a homeowner. This is important not only to
avoid unsightly messes, but also to prevent the enthusiastic birds from
hurting themselves. Sometimes, all it takes is moving a vehicle or
covering its mirrors, but often the only final solution is patience,
for the birds will soon be too busy raising a family to continue the
behavior.
Do come out to the farm and visit us
one of the next two weekends at
our open houses. There will be lots of birds, and also wildflowers to
see and purchase if you wish, as well as tours of the woodworking
business. We’ll be looking for you.
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April 19, 2011:
Consider the sparrow...
When many people speak of sparrows, they are usually thinking of the
house sparrow, a plump brown and gray bird with a black bib. It is a
noisy creature that can be found almost anywhere in town or rural areas
and flies about in small flocks, pecking around on the ground. It
occurs naturally and without a problem in most of Europe and Asia, but
has followed humans all over the world and thrived. In the United
States it is usually known as the 'English Sparrow', to distinguish it
from native sparrow species, and the birds we see are descended from
birds imported from Britain between 1850 and 1875 as a means of pest
control.
Along with two other introduced species, the European starling and the
rock pigeon, these are some of our most common birds. Though described
as tame and semi-domestic, they remain wary at the same time that they
take advantage of human food and shelter. At least three broods are
reared in a season and now in mid-April, nest-building has already well
begun. The nest is typically an untidy litter of straw and rubbish,
abundantly filled with feathers.
While the house sparrow has been around all winter, three other native
American sparrows are just arriving back from their winter migration.
The song sparrow, field sparrow and chipping sparrow spend the summer
in our area and might be confused with it, although they are members of
a different bird family and display none of the undesirable behavior of
that bird.
Listen for the song sparrow, a russet-and-gray bird with bold streaks
down its white chest. It perches on the tip of a branch of a low shrub
or tree and sings its beautiful song. It is found throughout most of
North America, but it varies in size and coloration depending upon its
location. Like many other songbirds, the male uses its song to
attract a mate as well as defend its territory, and females have been
observed to prefer the mates whose songs are most complicated and
varied.
The song sparrow nest is usually placed near the ground in a clump of
grasses or weeds, sometimes even close to human habitation in the
garden. The female normally only lays only one clutch of eggs each
breeding season unless the nest is destroyed, although in exceptionally
good conditions, one female was seen to rear four broods. The nest is a
simple, sturdy cup made of loose grasses, weeds, and bark on the
outside, and lined with grasses, rootlets, and animal hair.
Song sparrows eat mainly seeds and fruits, but also feed on many kinds
of insects and other small creatures in summer. They walk or hop on the
ground and flit through branches, grass, and weeds. Courting birds fly
together, fluttering their wings, with tails cocked up and legs
dangling. They are primarily monogamous, but up to 20 percent of all
song sparrows sire young with multiple mates each breeding season. In
fall, they may band together in loose flocks and often fly from perch
to perch, characteristically pumping their tails downward as they fly.
The smaller field sparrow is also singing right now, a simple, yet
distinctive song of repeated clear whistled notes on one pitch that
increase in rate until they make a trill. It is a common, drab sparrow
of brushy pastures and old fields and can best be identified by its
pink beak and reddish cap.
If a male field sparrow survives the winter, it usually returns to
breed in the same territory each year, and will begin to sing as soon
as it arrives. It sings until he finds a mate (usually not the same as
the past year’s as the female is less likely to return to the same
territory), but after that sings only occasionally.
The field sparrow typically will fly to the top of a grass or weed
stalk, let its weight carry the stem to the ground, and then begin
removing any seed. It also feeds on insects and other small creatures.
Its nest is placed on or near ground in a grass clump or at the base of
a shrub, and is an open cup of large grass blades interwoven with finer
grasses and lined with grasses, rootlets, and hair.
The third even smaller sparrow is the chipper. Its loud, trilling song
is one of the most common sounds of spring in woodlands and suburbs,
and the bird sports a bright rufous cap that makes adults fairly easy
to identify. When we had horses, we sometimes found their small
delicate nests made entirely of long hairs from tail or mane. Chipping
sparrows mainly eat seeds of a great variety of grasses and herbs, but
also hunt for insects and small fruits such as cherries.
The next time you see a small brown and gray bird hopping around on the
ground, take time to look and listen closely. It may be one of our
native American sparrows and you will enjoy learning to recognize the
three described above as well as others that also visit us. If you see
none in your area, come visit us at one of our wildflower openhouses,
April 30th and May 1st, or the following weekend. You likely will see
all three plus many lovely flowers.
------------------------------------------
April 12, 2011:
Hepatica: First Among Many
One of the minor miracles that occur every spring is the appearance of
the ephemeral woodland wildflowers. The snow has been gone and the
ground thawed for only a short time, and already the pink, white and
lavender blossoms of hepatica have opened in the woods. How do they
manage that? Some say that it is the protective downy hairs that cover
the hepatica flower buds when they emerge that may help insulate them
from the cool temperatures, while others think the moist earth probably
buffers the extremes of the day and night temperatures. Also, the
flowers close on cloudy cold days and at night.
Perhaps the hepatica can withstand the inclement days of early April
because of their makeup. Botanists tell us that the colorful parts of
their flowers are not petals but hardier sepals, modified leaves that
enclose and protect the pistil and stamens (the reproductive organs).
They also say that what appear to be three sepals just beneath the
stamens are actually another type of modified leaves called bracts. By
looking carefully, one can see that the bracts are not attached
immediately beneath the colorful flower parts as they would be if they
were sepals, but these terms make little differences to us
non-scientists who just enjoy their beauty. There are two sub-species,
a round-lobed variety and the pointed-lobed type, but only the shape of
their leaves separate them. The pistils and stamens turn green after
fertilization, and this is one characteristic used to separate this
plant from the closely related anemone.
The fact is that most of our native woodland wildflowers must bloom
before the trees leaf out. This strategy allows the plants to utilize
the sun’s energy to photosynthesize and thus make essential
carbohydrates while the sun’s rays are still able to reach the forest
floor. In some plants such as the Virginia bluebells and Dutchman’s
breeches, the plants complete their entire production of leaves,
flowers, and seeds within a few weeks and then disappear completely
until the following spring. These store the carbohydrate manufactured
by the leaves in underground tubers or corms that lie dormant
throughout the rest of the summer and winter, and so are able to
produce new plants quickly when spring arrives.
In the case of hepatica that has neither a tuber nor corm, the leaves
produced in the spring of one year remain on the plant through the
winter and into the next spring’s blooming period. It is thought that
these leaves may even photosynthesize to a minor extent on warm winter
days and are ready to begin full food manufacturing before the leaves
of other plants have even appeared. The old leaves wither only after
the flowers have begun to form seeds and by May, fresh green leaves
unfurl and begin to capture the sun’s energy once again for the coming
year’s growth.
The seeds of hepatica have a small, fleshy appendage called an elaisome
which is very attractive to ants. These insects collect the seeds and
carry them back to their nests where they consume the tasty part and
then discard the seeds that often then germinate and grow in their new
locations. Rodents, the prime consumer of most of the seeds, are less
likely to find all of them if they are spread out around the area
instead of just dropping below the mother plants, so the ants are
important agents in ensuring their survival.
Hepaticas may be the first flowers to bloom in the woods but several
other species join them in succeeding days. The blossoms of the spring
beauty are smaller but just as lovely, and more buds are present that
continue to open over a longer period. They have five white petals with
fine pink stripes, and their leaves are narrow and almost grass-like.
Both the leaves and stem rise from pea-sized underground corms that
Native Americans and early settlers found were very good to eat, and as
the plants spread into large patches, it was not difficult to find a
meal, despite their small size.
Bloodroot, whose name comes from the reddish sap found in its thick
branching rhizome, has a much larger and showier flower than either the
hepatica or spring beauty. Each flower bud emerges wrapped in a single
lobed leaf, and then opens to display eight to twelve delicate white
petals. The blossoms last only a day or two but the rhizome spreads
into a thick patch that usually continues to produce sprouts for
several weeks. The flowers are pollinated by small bees and flies, and
after the blossoms drop their petals, seeds develop in elongated green
pods. The leaves expand to their full size and eventually go dormant in
mid summer.
This is a lovely time to visit the woodlands. Mosquitoes, gnats and
deer flies are not yet a problem, and leafy foliage has not blocked the
view of the surrounding hills nor hidden the birds – both migrants and
nest-builders. Each day or two, new wildflowers will open their
blossoms and soon the shadbush and wild plum will be blooming as well.
Don’t miss them.
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April 5, 2011: Ever Seen a
Lichen?
This is the “in-between” period along
the trails – the snow is gone and
the branches of most trees and shrubs are bare, the grasses are brown
and mostly knocked flat, the colors are all grays and browns. Leaves
and flowers are present only in our dreams, but if you look closely you
can still find patches of bright green scattered here and there. Mosses
and lichens that go unnoticed most of the year stand out now and there
are more of these than you might think.
Lichens are often confused with
mosses, in part because many common
names for lichens include the word “moss.” In fact, the two organisms
are radically different and are not even in the same kingdom. Lichens
are fascinating, however, and often overlooked because they are small
and not very showy. They grow all over the world and are used for dyes,
animal fodder, ornamentation, medicines, and religious practices.
A lichen is unique because it is made
up of two very different
organisms that are completely dependent upon each other -- a fungus and
either algae or cyanobacteria (often called "blue-green algae").
Despite the “algae” name, cyanobacteria are units that live inside
cells, in contrast to algae that can vary from small, single-celled
organisms to complex multicellular forms and may resemble plants.
Cyanobacteria live in water, and can manufacture their own food but
because they are bacteria, they are quite small. They often grow in
colonies large enough to see, however, and have the distinction of
being related to the oldest known fossils, more than 3.5 billion years
old. They remain one of the largest and most important groups of
bacteria on earth.
Many Proterozoic oil deposits were
formed by the activity of
cyanobacteria, as was the oxygen atmosphere upon which we depend. They
are also important providers of nitrogen fertilizer in the cultivation
of rice and beans. The other great contribution of the cyanobacteria is
their role in the life of plants, living within their cells and making
their food in return for a home.
The symbiotic (mutually beneficial
relationship) nature of lichen was
not fully understood until the 19th century, when the idea was first
raised. Lichens form a fascinating example of cooperative relationships
in nature, with the fungus using the algae or bacteria to produce
energy, while the algae or bacteria enjoy the support and protection
the fungus provides.
Lichens take several forms. Some have
a brightly colored crusty
appearance and can be found growing flat on rocks. Others are leafy or
stringy and are often found on the ground or around trees. These
usually form stalks, which sometimes develop bright fruiting bodies.
Still others are gelatinous lichens that are made mostly of blue-green
algae with only a little fungus present. The gelatinous
appearance is from the mucilage commonly found on the exterior of
blue-green algae cells.
The body of most lichens is quite
different from those of either the
fungus or alga growing separately, and may resemble a simple plant. The
fungus surrounds the algal and cyanobacteria cells, and in many species
the fungus penetrates their cell walls. The algae and cyanobacteria use
sunlight to synthesize foods from carbon dioxide and water and reduce
atmospheric carbon dioxide into organic carbon sugars to feed the
lichen, while the fungus retains water, and sometimes provides minerals
obtained from the surface on which it lives. Both partners gain
water and mineral nutrients mainly from the atmosphere, through rain
and dust.
Lichens reproduce in several ways.
Many produce fungal spores that then
attempt to capture partner algae or bacteria, while others reproduce
through fragments of the lichen that break off and scatter. They do not
have roots and so can grow in locations impossible for most plants such
as arctic tundra, hot deserts, rocky coasts, and toxic slag heaps – but
they are also abundant on leaves and branches in rain forests and
Midwestern woodland, on bare rock, and on exposed soil surfaces.
Lichens are widespread and may be long-lived and may be useful to
scientists in assessing the effects of air pollution, ozone depletion,
and metal contamination.
Moss, on the other hand, is a plant
and one of the most genetically
diverse on Earth, including some 10,000 species. Moss can be found all
over the world as well, and it forms a major role by holding back
erosion, retaining water, and feeding numerous animal and insect
species. Moss has been around in various forms for millions of years,
and it reproduces by casting out spores. Like lichen, moss can also
reproduce from broken off parts of the parent plant.
I never really believe in spring’s
arrival when crocuses and other
domestic flowers bloom in the garden, as they are often fooled into
appearing too early, but since I began this article, the temperatures
outdoors have moderated a bit and the first buds have opened on the
hepatica in the woods. Now that is something to celebrate!
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March 29,
2011: Turkey Vultures Perform a Vital Service
I’m a week late with this news but
decided to report it anyway on the
slight chance that you might want to put the occasion on your calendar
for next year. Every March 15 since 1957, the city of Hinckley, Ohio,
has eagerly awaited the return of the buzzards. The celebration starts
at 6:30 AM at the Hinckley Reservation where early risers share coffee
and treats and compete for the first sighting. The buzzard has become a
sort of local folk hero, and, among other things, it has been the
mascot and logo for Cleveland rock station, WMMS, "the Home of the
Buzzard" for decades.
“Buzzard” is a common name for the
turkey vulture. This large bird with
the bald red head is native to the Americas from southern Canada to the
tip of Cape Horn. The typical adult has a six-foot wingspan and weighs
only about 3 pounds. Its body feathers are mostly brownish-black, but
the feathers on the wings appear to be silvery-gray beneath. It is
awkward on the ground with an ungainly, hopping walk but is beautiful
in flight. While soaring, it holds its wings in a shallow V-shape and
often tips from side to side, frequently causing the gray flight
feathers to appear silvery as they catch the light.
The turkey vulture plays a critical
role in our environment as it helps
recycle the bodies of dead animals, and the lack of feathers on the
head seems to play an important role in keeping the bird clean of
contamination. The corrosive enzymes in its stomach and sophisticated
immune system are able to kill a number of deadly organisms, including
salmonella and bacteria that cause anthrax, hog cholera, and botulism.
In India, South Africa and Spain some
years ago, vultures were maligned
as undesirable ugly carrion feeders and their populations plummeted due
to poisoning, shootings and an avian virus. Eventually it was realized
that their disappearance was accompanied with an increase in disease
and polluted waters. Finally, the governments of these countries
established captive breeding programs to reestablish the populations,
and today “vulture restaurants” have been created to ensure that these
increasingly endangered birds survive.
Turkey vultures are very social birds
that mate for life. They
are slow breeders but can live to be 40-50 years old. The birds
soar together in groups, sometimes forming large spiraling “kettles” as
they catch updrafts. The breeding season takes place in the spring and
courtship rituals involve several birds gathering in a circle, where
they perform hopping movements around the perimeter of the ring with
wings partially spread. These actions take place in relative silence as
the birds lack a syrinx (a avian voice box) and can only utter hisses
and grunts.
The female generally lays two
cream-colored spotted eggs on the bare
rock or ground in a protected outcropping, a burrow, inside a hollow
tree, or in a thicket. Both parents incubate, and the helpless young
hatch after 30 to 40 days. Both adults feed the chicks by regurgitating
food for them, and the young fledge at about nine to ten weeks although
family groups remain together until fall.
The turkey vulture has excellent
eyesight and can see a dead animal
from afar and also keep an eye out for other vultures that may have
found a meal. It is particularly fond of dead snakes but will also take
advantage of road kill of any type. When food is scarce, it has
also been known to eat vegetables such as rotting pumpkins and
sometimes fruit and grasses. In addition to sight, the turkey vulture
forages by smell, an ability that is uncommon among birds. The
olfactory lobe of its brain, responsible for processing smells, is
particularly large compared to that of other animals. However, the
carrion needs to be at least 12 days old for them to smell and they
prefer freshly dead animals to those that are more decayed.
At night, the vultures roost
communally, often using the same sites for
generations. Come morning, they are often seen high in a tree with
their wings outstretched to the sun. Their wings have long hollow bones
filled with air and as the sunshine warms them, the air in their wing
bones expands, making it easier to fly.
The turkey vulture has few natural
predators. Its primary form of
defense is regurgitating semi-digested meat, a foul-smelling substance
that deters most creatures intent on attacking the bird or raiding its
nest. The corrosive vomit will sting the face and eyes of any predator
that gets close and seems to send it scurrying.
In the fall, turkey vultures migrate
southward, soaring in great
circles that steadily move southward through Mexico and Central America
and other points further south. The winter is spent cruising the
rainforest canopy searching for food, and in late winter, they begin
movement back north. They often ride the winds of storm fronts, and
have been observed flying as high as four miles. More often than not,
they arrive in the Midwest on or about the Vernal Equinox (around March
20th), right in time for the Turkey Vulture Festival in Hinckley. We
saw the first arrival circling over the farm on March 21, so it was
right on schedule. These birds should be welcomed for the incredibly
important service they provide.
-------------------------------------------------------
March 22, 2011:
Eyes Up for the Whooping Cranes!
Imagine a bird that is five feet tall, has a wingspread of 7 ½
feet and can live about 25 years with a little luck. This describes an
adult whooping crane, a giant white bird with a red crown and a long,
dark, pointed bill. Flying overhead, the whooper shows black wing tips
on its white wings, a long neck held straight out ahead and long dark
legs trailing behind. The only other very large, long-legged white
birds in North America are the great egret, the great white heron, and
the wood stork, all of which are at least a third smaller than the
whooping crane. Herons and storks also have quite a different body
structure from the crane, usually crooking their necks as they fly.
At one time whooping cranes were relatively common in North America and
there were thought to be some 15,000-20,000 of them. Then, in the
1800’s and early 1900’s, habitat loss and hunting drastically reduced
their numbers. By 1860 their population had fallen to less than 1400,
and by 1941, only 15 whoopers were known to exist – all members of a
small flock that migrated between Wood Buffalo National Park in Canada
and the Aransas National Wildlife Refuge on the Texas coast.
Conservationists worked with local, federal and international
governments to protect the flock and encourage breeding. The whooping
crane was declared endangered in 1967 and by 1970 there were 57
birds.
Several attempts have been made to establish new breeding populations
in other areas due to the very real concern that a disaster might
strike a single flock. In 1975, the United States Fish and Wildlife
Service and the Canadian Wildlife Service initiated a project that
involved placing whooper eggs in the nests of sandhill cranes. Although
85 chicks from the 289 whooping crane eggs did hatch and grow up to
migrate, they imprinted on their sandhill foster parents and refused to
mate with their own species.
A second effort involved the establishment of a non-migratory
population near Kissimmee, Florida and this area now is home to about
22 cranes. There have been major problems with them, however, as they
have had a high mortality rate due to accidents and predators and they
also have not reproduced as hoped. It was finally decided that no
further birds would be added to that flock although research continues.
The third and most successful attempt has involved teaching new
generations of cranes to migrate down a flyway laid out east of the
Mississippi river. Young whooping cranes were raised in isolation at
the Necedah National Wildlife Refuge in Wisconsin and trained to follow
ultralight aircraft to a winter refuge in Florida. This reintroduction
began in the fall of 2001 and new groups of birds have been led south
each autumn since. Most of these cranes have returned to Wisconsin each
spring and finally, in 2006, two whooper chicks were hatched of parents
that were led by ultralight on their first migration in 2002, the first
whooping cranes hatched in the wild of migrating parents east of the
Mississippi in over 100 years.
Whooping cranes nest on the ground, usually on a raised area in a
marsh. The female lays 1 or 2 blotchy, olive-colored eggs, usually in
late-April to mid-May. The eggs average 2½ inches by 4 inches
and hatch in about 30 days. Both parents brood the young, although the
female spends the most time on the nest, and the parents feed the young
for 6–8 months after birth. These birds forage while walking in shallow
water or in fields, feeding on various crustaceans, mollusks, fish
(such as eel), berries, small reptiles and aquatic plants as well as
waste grain, including wheat and barley, during migration.
Adults have very few predators, as even eagles are unlikely to be able
to tackle one, but the young are vulnerable to a number of predators
until they can fly. The bobcat is the only natural predator known to be
both powerful and stealthy enough to prey on adult whooping cranes away
from their nesting grounds.
The Aransas/Wood Buffalo flock is the only naturally occurring wild
migratory population of whooping cranes in the whole world, and every
whooper alive today either hatched at the Canadian nesting grounds or
is a descendant of a whooper that hatched there. This year, on a
February flight over the Aransas/Wood Buffalo refuge, an observer
counted 238 adults and 42 juveniles for a total of 280 whooping cranes.
With the addition of a confirmed report on February 8th of a single
whooping crane in north Texas, the flock size is now thought to be 281.
The Necedah/Florida flock numbers 101 at the beginning of March this
year. As of last week, all the youngest cranes are still at their
Florida release sites, but migration has begun. Just one early
bird from the western flock is migrating, but at least 25 older cranes
in the eastern flock are on the journey north. One pair was back on the
Wisconsin nesting grounds on March 9, and others have been seen in
Indiana. A friend at church reported that he saw one overhead two weeks
ago, so keep your eyes and ears open for the big birds. What a thrill
it would be to see one!
-----------------------------------------------------------
March 15, 2011: Have You Ever Seen a
Mole?
Some biologists have said that the
Eastern mole is the least understood
of all the American mammals and as far as I could discover, most of the
research done about it has been concerned only with killing it off. It
certainly is a strange animal. No sooner is the snow cover gone and the
frost out of the ground than lawns and other grassy areas are dotted
with mounds of dirt, sometimes arranged in long lines and sometimes
seemingly randomly placed. The mole is a veritable digging machine,
equipped with specialized shoulders and front legs ending in large wide
forefeet. It seldom emerges from its maze of underground tunnels and
when it does it is only to get rid of excess dirt from its excavations.
The Eastern mole is about six inches
long and weighs about four ounces.
Its body is covered with a thick velvety fur (unique in that it has no
pile direction so that the animal can go forward or backward in a
tunnel with ease) and it has a short, scaly, hairless tail. It finds
its way around and detects prey by its acute senses of smell and touch
as it has only rudimentary eyes partially covered with skin that do
little but perceive light, and no external ears, although it can detect
vibrations and some sounds.
One study found that a male mole
ranges under an area of perhaps 300 by
400 yards, while a female tends to stay in an area of about 60 by 60
yards. Home ranges often overlap and several individuals have been
found using the same tunnel systems. Some of the passageways are deep
and relatively permanent that are used as burrows and as routes to
feeding sites while others are closer to the surface and used as
runways for collecting food. Winter tunnels tend to be deeper than
summer tunnels as the animals are active all year long and must stay
beneath any frost layer.
Moles can dig tunnels up to 5 yards
long in one hour using their large
powerful forefeet. When they burrow, they essentially "dive" into the
earth; they first thrust their forefeet into the soil and then follow
with the head and body as they rotate their forelimbs and pull the
loosened dirt backwards. Because of specialized bone and muscle
construction, moles can exert a lateral digging force equivalent to 32
times its body weight. (As a comparison, a 150 lb. man would be able to
exert a 4800 lb. lateral force.) The energy required to construct a
permanent tunnel system is great and to protect his work the mole scent
marks most of the home range daily as it travels through the system in
search of food. This warns other moles that the system is occupied and
may advertise a female’s scent when she is ready to mate, a signal
easily picked up by a rutting male crossing her tunnel.
A mole has twice as much blood and
twice as much red hemoglobin as
other mammals of similar size, allowing it to breath easily in its
underground environment of low oxygen and high carbon dioxide. Its main
prey is earthworms but also eats insects and their larvae, as well as
some vegetable matter. A mole has high-energy requirements and will
consume up to 100% of its body weight in food each day—some 45 to 50
lbs. of worms and insects per year. It also aerates and turns soil
through its extensive tunneling activities, although these often damage
pastures and garden by injuring bulbs and root masses and bring down
the wrath of the landowner.
In late March and early April, a male
will start to move around in
search of females. He will mate with any he can find, continuing until
no more can be found. After mating, the female prepares a nest chamber
of dry vegetation underneath a boulder or the roots of a plant, and in
about five weeks gives birth to two to five young. They are cared for
and nursed by their mother in her nest and tunnel system until they are
weaned. Then they continue to share her tunnel system for about a month
until they are able to forage on their own, when they leave and
establish their own tunnel systems.
Strange as the Eastern mole seems, an
even more bizarre mole also can
be found in Wisconsin -- the star-nosed mole. It reportedly prefers low
wetlands, but we have seen one here one the farm. Its nose is a highly
specialized sensory-motor organ, consisting of 11 pairs of fleshy
finger-like appendages that look something like a pair of sea anemones
perched on its face. Although the nose is less than half an inch in
diameter, its surface is covered with 25,000 mechanoreceptors called
Eimer's organs. (That makes it the most sensitive organ in the entire
animal kingdom--about 6 times more sensitive than the human hand, which
contains about 17,000 receptors.)
The mole’s nose substitutes for its
missing eyes, and approximately
half of its brain is devoted to processing sensory information from it.
The star-nosed mole can touch 13 separate areas of the ground every
second, and can locate and consume 8 separate prey items in under 2
seconds. Once prey has been identified, it is captured with
tweezer-like incisors, whose movements are coordinated with those of
the star. If I hadn’t seen one of these weird creatures myself, I might
have believed it was one of Alice’s friends escaped from Wonderland.
-----------------------------------------------
March 8, 2011: Consider the Bluebird
The flash of blue on the telephone
wire along the road was a welcome
sign that spring really is imminent. Granted that bluebirds sometimes
stick around all winter when the weather is open and mild, this
certainly hadn’t been the case this year and I was sure that this
sighting was significant.
The Eastern bluebird is a small thrush
with a big, rounded head, large
eye, plump body, and alert posture. The males are vivid, deep blue
above and brick-red on the throat and breast although the color blue in
birds always depends on the light, and males may look plain gray-brown
from a distance. Females are grayish above with bluish wings and tail,
and a faded orange-brown breast.
Bluebirds need mixed prairie
surrounded by trees that offer suitable
nest holes. They feed mostly on insects during the summer, either
hunting in the grass or snatching them from the air, and fruits and
berries during the fall and winter. As settlers cleared the eastern
forests for homesteads and pasture, they created large, open areas that
provided exactly the kind of habitat that the birds needed, and they
quickly moved into it. Forest clearing reached its peak around 1830,
and as an additional bonus to the birds, wooden fence posts were
erected around fields that provided additional nesting holes as they
rotted and woodpeckers created and then abandoned cavities searching
for grubs.
A major problem arose about the same
time, however, as English sparrows
and European starlings were introduced into the countryside, both very
aggressive cavity nesters that competed with the bluebirds for nest
sites. Then, too, it gradually became common farming practice to clear
out fencerows, install steel fence posts, and cut any dead or dying
trees, thus eliminating nesting sites. The bluebird numbers declined
drastically until the 1970’s when the problem was recognized and bird
lovers began providing and monitoring nest boxes throughout the eastern
half of the country.
In early March, bluebirds start
checking out nesting sites. The adult
male bluebird typically selects a suitable cavity and will begin
carrying in nesting materials consisting of straw, grass and pine
needles. When a female appears, the male will sing and flutter, wings
half open, tail spread. It then perches near the female, preening her
feathers, and may offer food. If the female accepts him, the two will
mate and may stay together for several seasons.
Only the female will build the nest.
She begins by weaving the straw,
pine needles, or similar materials into a typical bowl shaped nest that
may be several inches tall inside the cavity. She will then line it
with fine grasses and occasionally a few feathers. It usually takes
several days to construct a nest to her satisfaction and it is another
couple of days before she will lay her first egg. She will continue to
lay an egg a day until her clutch is complete, usually four or five but
sometimes as many as seven eggs.
The female will not begin to brood her
eggs until all are laid, and
then it takes about 18 days before they hatch – usually with in a few
hours of each other. The chicks are naked and helpless, but in just
four weeks, they will have left the nest and be flying. The male
continues to feed the youngsters a few more days until they have
learned to feed themselves, while the female lays another clutch of
eggs and begins another family.
In late August and September,
bluebirds molt, and it is at this time
that the young of the year loose their spotted breasts so that they
resemble adults. Some of them winter in the southeastern states and
even down into Central America, but if food is plentiful they sometimes
stay in the vicinity of their nesting area. Small flocks of wintering
bluebirds are not an uncommon sight in southern Wisconsin, feeding on
native berry-producing shrubs such as red cedar, grapes, and dogwood.
They ordinarily do not visit feeders but sometimes can be enticed to
take mealworms or a mix of peanut butter, oatmeal, and yellow cornmeal
held together with melted suet.
There are two other bluebirds in the
United States – the Western and
mountain bluebirds. Male Western bluebirds have a fully blue throat and
chestnut shoulders while male mountain bluebirds are mostly a lighter
sky blue all over, without the reddish underparts. Female bluebirds are
more difficult to distinguish, but the Western and Mountains have dark
or dusky (not white) chins, and a grayish rather than clear white
belly. The ranges of Western and mountain bluebirds only overlap a
little with Eastern bluebirds, mainly in central and west Texas. You
should never confuse any of the three with male indigo buntings that
are entirely blue and considerably smaller, with the thick beak of a
finch.
When I walked out onto the deck this
morning I was greeted by a melody
of song – bluebird, cardinal, titmouse, chickadee, and I was sure I
heard a redwing in the distance. What a treat that is!
----------------------------------------------------------------
March 1, 2011: Feet and Tracks
Hiking up the trail to the ridge is
much easier this week than last, as
the snow depth has been reduced to an inch or two in most places and
only in scattered areas is it still deep. Many times during the summer
when I walk the paths, I don’t see a single creature except an
occasional bird, and that was the case on this week’s treks as well.
The big difference is that, although I may not see anything, the last
two inches of snow cover and our recent milder weather has provided a
perfect canvas for recording tracks, and the evidences are plain that
lots of animals and birds are present and moving around.
Deer are, of course, the most obvious
travelers, but squirrels and
rabbits also hop from tree to tree and bush to bush in considerable
numbers. A raccoon walked along this way, and an opossum ambled that. A
flock of turkeys walked down the trail, dragging their feet as they
went and leaving long stripes. There are surprisingly few mouse prints,
compared to a few weeks ago, but perhaps they are staying underground
or under what snow there is, as we know they are there.
It is interesting to observe the great
variations in the feet that make
the prints, and these are often uniquely suited to their owner’s
lifestyle and environment. Even what an animal eats can depend on what
kind of foot it has to help it get to that food.
All species can generally be divided
into three types: those that place
the full length of their foot on the ground such as humans and bears;
those that walk with most of the length of their digits but not the
soles in contact with the ground such as dogs and cats; and those that
travel on the bones of their toes with their wrists and ankles held off
the ground, such as deer and horses. Deer feet are actually two
elongated toes comparable to the third and fourth fingers on one’s
hand, with the second and fifth "fingers" located behind the hooves and
called dewclaws. Their hooves are like big, thick toenails.
A dog walks on his toes like a deer,
but its foot has four pads on the
ground, each with its own toenail. Those parts of the foot that are
similar to the human wrist and palm of the hand are held off the ground
and we usually think of them as its lower leg. Animals adapted
for speed like deer, have relatively longer lower limb segments;
however, their feet tend to be relatively useless as tools. On the
other hand, a dog's paws are not as helpful in running as the feet of a
deer, but can dig and hold some objects, while cats, still less adept
at running, have arms and paws that that can grasp things.
Animals that hunt and kill their food
need feet that are padded so they
can quietly sneak up on their prey and sharp claws to catch and kill
it. Other animals need feet that will allow them to escape predators by
running or climbing. Animals that live in the water need feet that help
them swim, and some have feet much like ours with toes and padded
soles, but with toes that can curl round tree branches. Climbing claws
are curved and sharply pointed to dig into tree bark while digging
claws are broad and blunt, and burrowers often have wide, flat paws
that that act like scoops or shovels, sometimes made wider by fur or
bristles.
All birds are toe-runners, and the
various species have feet designed
for running, perching, grasping, wading, and paddling. Most songbirds
have four toes with the first big toe turned backward while the other
three forward as it needs opposing toes that wrap around a twig. Birds
that usually run on the ground often have the backward toe higher up
the leg out of the way, and possess thick, powerful toes with well
developed nails. Swifts, that can hang on vertical surfaces, have all
their toes turned forward, while woodpeckers are equipped with two toes
forward and two backward. In ducks, the three front toes are connected
with a web of skin.
Knowing something about the feet of
the various creatures is a big help
in identifying the tracks one sees in the snow or in mud or dust. This
is perhaps far more than you wanted to know about tracks unless you are
a hiker and are out these late winter days. Then you will want to note
the number of toes on the track and other details, and with a little
luck, you will be able to identify all those other creatures that have
passed by. Knowing your neighbors gives an added enjoyment to your
outdoor sorties.
It snowed again last night and the
ground is covered with a sparkling
fresh blanket. I used to think it as being white, but realize now that
was only my limited perception. As I look out upon the deck, yard, and
neighboring field I see many shades of blue, gray, and now gold where
the rising sun is striking it.
Many people travel to far places where
warm temperatures and green
grass and flowers await, but to us, the winter landscape is part of
Wisconsin’s lure. It is like living in two very different worlds, and
experiencing one makes the other more interesting and pleasurable.
--------------------------------------------------
February 21, 2011: And
Skunks.... Oh, My!
We are always on the watch for animals
at the edge of the road but the
skunk that appeared almost under our wheels the other afternoon took us
by complete surprise. It is common for skunks, raccoons, and opossums
to venture abroad as temperatures moderate, but this was before the
current warm-up and I can’t imagine why it was out. In any case, there
was a soft thump and the car filled with the strong odor that almost
everybody knows is very bad news.
Skunks are best known for their
ability to secrete an oily, pale-yellow
liquid with a strong, foul odor that they can use as a defensive
weapon. They have two scent glands, one on each side of the anus and
these produce a mixture of sulfur-containing chemicals such as methyl
and butyl thiols traditionally called mercaptans, which have a highly
offensive smell often described as a combination of rotten eggs, garlic
and burnt rubber. Muscles located next to the scent glands allow them
to spray with a high degree of accuracy, as far as ten to fifteen feet.
The smell aside, the spray can cause irritation and even temporary
blindness and is sufficiently powerful to be detected by a human nose
anywhere up to a mile downwind. The odor of the fluid is strong enough
to ward off bears and other potential attackers and can be difficult to
remove from clothing and a car.
Skunks are reluctant to use this
weapon, as they carry just enough of
the chemical for five or six uses – about 15 cc – and require some ten
days to produce another supply. Their bold black and white coloring
however serves to make the skunk's appearance memorable to any creature
that has come into contact with one. Where practical, it is to a
skunk's advantage simply to issue a warning without expending scent and
one does this by the use an elaborate routine of hisses, foot stamping,
and tail-high threat postures before resorting to the spray.
Interestingly, skunks usually do not spray other skunks, with the
exception of males in the mating season. Though they fight over den
space in autumn, they do so with teeth and claws.
Skunk spray is detectable by the human
nose at concentrations of only
10 parts per billion. The smelly compounds are also mixed with other
chemicals that make the scent stick. This is why dogs that have been
sprayed sometimes have a faint skunky odor for several weeks, because
although the chemicals have been mostly neutralized, trace amounts
still cling to fur. I read that the chemicals which cause skunk spray
to cling are now used in cosmetics and perfumes for lasting odor power,
after the thiols have been removed.
It is easy to take one’s sense of
smell for granted (unless it is lost)
and forget that in order to detect the odor of something, molecules
from that thing have to make it to the nose. Everything one smells is
giving off molecules, and these are generally light, easily evaporated
chemicals that float through the air into your nose. At the top of your
nasal passages behind your nose, there is a patch of special neurons
about the size of a postage stamp. These have hair-like projections
called cilia that increase their surface area, and an odor molecule
must bind to these cilia to trigger the neuron and cause you to
perceive a smell. We are told that humans can distinguish more than
10,000 different smells, and it is thought that there are hundreds of
olfactory receptors, each encoded by a different gene, each recognizing
different odors.
The importance and sensitivity of
smell varies among different
organisms; most mammals have a good sense of smell, particularly
carnivores and hoofed animals that must always keep track of each
other. It is estimated that most dogs have an olfactory sense
approximately a hundred-thousand to a million times more acute than a
human's, and bloodhounds, especially, have noses that are up to
one-hundred-million times more sensitive. They were bred for the
specific purpose of tracking humans, and can detect a days-old scent
trail. Even more receptive is the sense of smell of the silvertip
grizzly that is seven times greater than the bloodhound. Using their
elongated claws, these bears must be able to find burrowing animals and
nests as well as roots, bulbs, and insects deep in the soil or snow.
They can detect the scent of food from up to 18 miles away, and because
of their immense size they often scavenge new kills, even driving away
packs of wolves and human hunters.
.
There are a variety of remedies for
skunk spray, but only by
neutralizing the chemicals with hydrogen peroxide and baking soda is it
really possible to get rid of it. Even then the odor often lingers, and
clothing and other objects must be treated with bleach to completely
remove it. If this is impractical, and the smell has drifted throughout
your house or car, all you can do is air it out.
Wolves, foxes, coyotes and badgers
seldom attack skunks – presumably
having had a previous bad experience of being sprayed. An exception is
the great horned owl –– which, like most birds, has very little sense
of smell and is the animal's only serious predator. Vehicles are
probably their greatest threat, however, and a great number are killed
on the roads. We could find no sign of our animal, however, and it may
have survived its encounter. All that remains is its lingering smell.
-----------------------------------------------
February
14, 2011: The Cooper's Hawk
We were startled one day last week
when a bird crashed into the living
room window amid a great flurry of feathers. When the dust settled we
saw a medium-sized hawk sitting on the porch railing, peering around in
all directions. We stayed still to avoid scaring it off and waited for
it to jump down to the deck to grab its victim, but it was soon obvious
that its dinner had been able to escape both the hawk attack and the
window, and was gone.
It was only two weeks ago that I
confidently reported that the Cooper’s
hawks had moved south and had perhaps traveled as far as Panama, but
this bird obviously didn’t read my column. It had a pale breast
streaked with narrow crosswise bars and was about the size of a small
crow, with a large head, slender body, broad wings and a very long
tail. We thought at first it might be one of the look-alike
sharp-shinned hawks, but it had the distinctive rounded tail that
clinched the identification.
Among the bird world’s most skilful
flyers, Cooper’s hawks are now
relatively common in woodlands across the country and are most likely
to be seen cruising along a forest edge or above a field using just a
few stiff wing beats followed by a glide. Even when crossing large open
areas they rarely flap continuously. One typically flies with its neck
outstretched and has been described by birdwatchers as looking like a
"flying cross".
The Cooper’s hawk will attack almost
any medium-sized bird. Studies
list the European starling, mourning dove, and rock pigeon as common
targets along with the American robin, several kinds of jays, Northern
flicker, and quail, pheasants, grouse, and chicken. It typically tears
through tree canopies at high speed in pursuit of one of these birds,
but dashing through vegetation is a dangerous lifestyle. In a study of
more than 300 Cooper’s hawk skeletons, 23 percent showed old,
healed-over fractures in the bones of the chest, especially of the
wishbone. When it does snag a bird it kills it by squeezing it in its
razor-sharp talons, in contrast to the falcons that usually kill their
prey by biting them.
Courting birds display by flying with
slow wing beats, then gliding
with wings held in a V. As in most hawks, males are significantly
smaller than their mates and are in some danger as females specialize
in eating any medium-sized birds. Perhaps for this reason, males tend
to be submissive to females and to listen for the reassuring call notes
the females make when they are willing to be approached. The male makes
a bowing display to its mate after pairing, then does much of the work
of building the nest and providing nearly all the food for it and the
young over the next 90 days before the young fledge.
The nest is placed about two-thirds of
the way up on a horizontal
branch or in a crotch of a large tree, and is a pile of sticks about
two feet in diameter and a foot high with a cup-shaped depression in
the middle. The female usually lays 3 to 5 pale blue eggs and incubates
them between 30 to 36 days. The hatchlings are covered in white down
and weigh just one ounce, but are able to crawl around in the nest.
They are brooded for about two weeks and then the female sometimes
joins her mate foraging for food. The young leave the nest two weeks
later, but return to be fed until they become independent at around 8
weeks.
Not too long ago, Cooper's hawks were
considered to be “threatened”.
They were often called chicken hawks and shot on sight as they were
thought to prey on poultry, but it is now known that such attacks are
rare so they are seldom hunted these days. Also, their breeding success
was reduced by the use of the pesticide DDT, but the ban of DDT ended
that threat. Now the main threat is loss of habitat as logging often
makes what woodlands remain unsuitable for breeding. Still, Cooper’s
hawk population trends are strong today and they are increasingly seen
hunting smaller songbirds in backyards with feeders. They will perch in
trees overlooking the feeders, then swoop down and scatter the other
birds in order to capture one in flight. Now if they would just
concentrate on English sparrows...
----------------------------------------------
February 8, 2011: Two
Fierce Creatures
You probably have never seen a shrew,
and if you did happen upon one,
you might have thought it was a mouse with a very short tail. Luckily,
our common species -- the Northern short-tailed shrew -- grows only to
about five inches in length counting an inch-long tail and weighs only
about one ounce, for it has sharp, spike-like teeth and a voracious
appetite that causes it to eat 80-90 % of its own body weight in live
food daily. It incidentally is also among the very small number of
mammalian species that have venom glands. Shrew venom is a neurotoxin
that is powerful enough to immobilize or even kill small prey species
like frogs and mice and can cause swelling and irritation in humans.
Now, picture an animal that weighs
twice as much and is just as fierce
and hungry. This describes the least weasel, the smallest of the weasel
clan. It has an eight- to ten-inch slender body, short legs and a flat,
narrow head, with black eyes and round ears. In the winter its coat is
completely white, while in the summer its upperparts are a rich
chocolate brown over white underparts. This weasel uses a thick, oily
yellowish fluid with a very potent odor called musk to mark the borders
of its hunting area or territory. This is stored in special scent
glands that are located at the base of the weasel's tail and informs
other animals of its presence, sex, and activities.
We have only seen one of these elusive
weasels twice in the 40 years we
have owned the farm, but we know they are here. Weasels are easiest to
detect in winter when a thin layer of tracking snow will show where
they move about in the neighborhood. They leave staggered pairs of
little footprints placed in a bounding gait fashion that often make
sudden right-angle turns and seldom travel far in any one direction. A
weasel will stop to poke into every hole and cranny it can find and if
its sensitive nose and ears detect a tenant it will squeeze its slender
body into the tunnel after it.
The least weasel is active year-round
and spends its time, day and
night, hunting, feeding, and sleeping. When it hunts, it runs down its
victim, wraps itself around it and kills with a bite to the base of the
skull. Both male and female least weasels have body diameters no larger
than their prey, which allows them to follow a victim into a burrow,
tunnel, matted grass and even under the snow. When it is able, a weasel
will kill more than it can eat, and then stores the excess in its den
or in small caches scattered about for future meals.
Small rodents make up the majority of
the least weasel's diet, although
they can take prey larger than themselves, including rats and rabbits.
On average, this small carnivore must consume half of its body weight
every day to survive – the equivalent of at least two deer mice or one
meadow vole. When rodents are not readily available, the least weasel
will look for birds' eggs, nestlings, insects, and most anything that
moves.
The weasel has an interesting behavior
that has caused much speculation
through the years. After making a kill it often performs a frenzied
series of sideways and backwards hops, often accompanied by an arched
back and hissing noises. Observers have named this a “ weasel war
dance” and it is thought to be caused simply by its excitement in a
successful hunt, but it seems to be unique to these animals.
Most breeding occurs in spring and
late summer and females can have
multiple litters throughout the year. A litter may contain up to
six young and the kits are born wrinkled, naked, blind and deaf. In 11
days, they are covered with a fine white body hair, and by 18 days they
have brown hair on their backs with white bellies. At this point, they
are eating solid food and by the time they are five weeks old, they are
able to kill their own prey. Males reach sexual maturity at eight
months, while females reach maturity at four months.
Two other species of true weasels live
in Wisconsin. The largest, at 18
inches, is the long-tailed weasel. It seems to prefer an area near
water, while the smaller short-tailed weasel is more often found in
heavily-forested and brushy areas farther north. The short-tailed
weasel is known as an ermine in the winter when it is white, and its
pelt has long been highly prized and was used in the robes of the
royalty in England. These two species of weasels generally find mates
in late summer, but the young are not born until the following spring
in a strange process called delayed implantation. The embryos undergo
an initial development of about two weeks, then remain dormant in the
uterus for some eight months before implanting and continuing
growth.
Finding a meal is hard work for both
the shrews and weasels and
avoiding becoming a meal is even tougher as they have a multitude of
enemies but cannot afford to hide away. They have to travel about their
territories alert to every sound, every smell and every motion around
them. We've historically trapped shrews and weasels as pests, varmints
or scraps of fur only suitable for a decorative trim on collar or cuff.
In fact, both are valuable insect and rodent controls and play
important roles in our wild world.
--------------------------------------------------------
February 1, 2011: Where are all
the Birds?
With the temperatures often hovering
just above zero and the snow
blanket up to a foot deep in some places, it is comforting to know that
many of our summertime residents are basking in tropical lands. At the
same time, we know that a considerable number tough it out right here.
Mostly it has to do with available food. Berry eaters such as robins
and bluebirds can sometimes find sufficient supplies to stay fairly
close although they usually have to move around. Ground-bound creatures
such as woodchucks, ground squirrels, bats, snakes, turtles, and frogs
hibernate, and sleep out the winter months, while others such as bears,
skunks, raccoons, opossums are not "true" hibernators but take long
naps and are easily awakened from their winter slumbers if the weather
allows.
Insect-eating birds make up the most
of the travelers, and the
distances some of them cover are hard to believe. Our tiniest species
is the ruby throated hummingbird that crosses the Gulf of Mexico to
winter on the Yucatan Peninsula and beyond. (It was once believed that
so fragile a bird could not accomplish such a trip by itself and must
travel on the back of a larger bird.) Other small birds that join them
there for the worst weather months are the several warblers that nest
here at the farm – the yellow, blue winged, and redstart.
How the various species evolved to act
as they do is hard to
understand. The robin and bluebird are close relatives of the wood
thrush, but while they both can sometimes be seen about during mild
winter periods, the latter bird will make its way as far as Panama
every year. Among the woodpeckers, the red-bellied, pileated,
downy, hairy, and red-headed stay all year, while the sapsucker and
flicker migrate. The kestrel (a small falcon) can be seen sitting on a
wire watching for prey at almost any time, while the closely related
sharp-shinned and Cooper’s hawks head for warmer climes in the fall.
Most amazing among the travelers are a
few of our very common birds.
The barn swallow is one of our favorites here at the farm and is easily
identified by its long, deeply forked tail, deep blue back and
orange-buff breast and belly. It can be seen all summer long foraging
low over fields and water snagging flying insects. These swallows are
reported to fly in large flocks across Central America, traveling as
much as 600 miles a day. You would think they might just stop there in
such an inviting tropical area, but instead, sometimes go on to all the
way through South America as far south as Argentina.
Two other closely related species that
migrate to far places are the
whip-poor-will and the nighthawk. Both are medium-sized
well-camouflaged birds that forage at night, although the
whip-poor-will is a bird of the countryside while the nighthawk is more
commonly seen above lighted parking lots at shopping centers. They,
like the swallows, migrate to Central and South America, following the
Texas coastline down through Mexico.
Several of the flycatchers – such as
the kingbird and peewee – also
winter in South America. The kingbird has a dark head and back over a
white chest and belly, although its most distinguishing marks are the
white ends of the tail feathers. The peewee is smaller with rather drab
grey plumage, and wing bars. Both species move down to the Gulf States
in the autumn, and then follow the coast west through Texas into
Mexico. I suppose some may drop off along the way, but many keep going
into Columbia and Brazil, traveling thousands of miles each way.
Eastern phoebes – another common
flycatcher here at the farm -- are
quite hardy for a bird that feeds extensively on flying insects, and
are regularly found throughout the southern United States and Mexico in
winter. To survive cold spells, they supplement their diet with fruits
such as sumac, poison ivy, bayberry, and holly. Over 20% of their
winter diet can be comprised of fruit, compared to less than 5% in
spring and summer.
Most of our other migrants spend the
winter in the southern states
rather than make a longer trip. The catbird goes to Florida, as do the
flicker and sapsucker. Our friendly little chipping and song sparrows
can often be found in Florida and Texas, although some don’t go any
farther south than Tennessee and Kentucky. The red-winged blackbird and
towhee will stay throughout the lower mid-west unless deep snows there
force them farther south, and house wrens are known to winter in
northern Mississippi and Louisiana.
Migration is not a pleasure trip for
the birds. They must move long
distances through unfamiliar territories with unknown perils, sometimes
encountering big bodies of water and high mountains. Their destinations
are already populated with resident birds that undoubtedly object to
their arrival, and the food supply must stretch to accommodate them.
Still, most survive, and will soon return to gladden our hearts.
------------------------------------------------------
January 25, 2011: The Bob-tailed Cat
There is a picture going around on the
Internet in our area of a bobcat
that was trapped in a coyote leg trap somewhere nearby. Historically
bobcats were abundant throughout the state, but logging and settlement
reduced their ranges. Also, they were thought to be a threat to
livestock by early settlers, and killed whenever found. Now sightings
are very rare in the southern half of the state. We have heard
rumors of the wild cats living here through the years, but this is the
first actual proof we have seen. Imagine meeting a cat twice the
size of your house pet and weighing 20-30 pounds.
The bobcat has large ears that have
pointed tufts of hair at the ends,
an orange-tan coat with black stripes on the face and spots on the
body, and a short tail that is black on the top and white beneath. It
can be confused with the lynx, an animal found farther north, but the
bobcat has smaller footpads, a slightly longer tail, shorter black ear
tuffs and more well-defined spotting on the coat. Bobcats are on the
move during twilight hours of sunrise and sunset during the summer, but
on winter days they may be abroad at any time. Male bobcats often
cruise a 25-square-mile area and females somewhat less. Young bobcats
may wander as much as 100 miles to find an unoccupied territory to make
their home.
Each week they travel many miles along
logging roads, railways, and
trails made by other animals to move between resting areas, food
sources, or hunting areas, marking their territory boundaries with
feces, urine, and gland secretions. The bobcat is strictly carnivorous
and the largest percentage of its diet is comprised of rabbit,
squirrel, and sick or injured white-tailed deer. It will also
feed on smaller rodents, shrews, reptiles, birds, turkey, grouse, and
even insects, but prefers rabbit-sized animals. The bobcat has been
known to occasionally feed on carrion but only when relatively fresh.
When it finishes eating, it will sometimes cover up any remaining
portions with sticks or leaves for later consumption.
Bobcats will take several different
mates throughout their lifetime.
The young become sexually mature at about 9-12 months but a pair
typically will have its first litter of kittens at two years of age.
The female will establish a den in a cave, rock crevice or hollow log,
and carefully line it with dry leaves, moss, or grass. Two or three
10-12 ounce kits are born between April and July. They are fully
furred, although it is 10 days before their eyes open. They grow
quickly and at 4 weeks old, they will leave the den and eat solid foods
caught by their mother (the father does not aid in raising the young).
The kitten's survival depends mostly on how much prey the mother is
able to catch.
In Wisconsin, it is legal to harvest
bobcats by both trapping and
hunting. The first attempt to manage their numbers was in 1867 when a
$10 bounty was offered. The payments were reduced to $5 per
animal in 1923 and over the next 40 years, an around 400 animals were
taken each year, resulting in a greatly reduced population, living
mostly in the northern third of the state. Bounties ended in 1963
and the first regulated harvest season took place in 1970. In 1980, a
season bag limit of 1 bobcat per hunter/trapper was set, as well as a
protection of bobcats south of State Highway 64. In 1983 the harvest
season length was set at 2.3 months and the WDNR made it mandatory to
turn in the carcasses for collection of age, sex, and reproductive
information.
As of 2003, the WDNR estimated the
bobcat population in Wisconsin to be
2,590 animals, with the bulk of the animals in the northern half of the
state and only occasional sightings reported as far south as Dane,
Iowa, and Sauk counties. Records show that 253 bobcats were
harvested in the state for 2002. Some wildlife supporters have
pressured the state to halt all hunting and trapping of these animals,
arguing that their numbers are dropping each year, but at this point,
the WDNR has no such plans.
The fate of the trapped cat described
above is unknown, but the word is
that it did not seem to be severely injured and was released. We were
pleased to hear this, but we did wonder who was brave enough to open
the trap...
-----------------------------------------------------
January 18, 2011: Owls: The
First Sign of Spring
While we may feel like we are in the
midst of a never-ending
winter—getting up and eating dinner in the dark, experiencing snow
after snow with bitter winds to boot—some creatures out in the wild are
thinking Spring! If you have ventured out into the woods lately, you
very well may have been entertained by a pair of great horned owls
dueting in the woods. The song is a series of five to seven muffled
hoots and can be heard over several miles. The male, though smaller
than the female, has a deeper voice, so it’s easy to recognize a
breeding pair.
The great horned owl is a large bird
that may have a wingspan of up to
five feet and stand two feet tall. Its back can vary in color from a
reddish brown to a grey but its underside is a light grey with dark
bars with a white band of feathers on the upper breast. If you can get
close enough to see its head, you will see large, staring yellow-orange
eyes set in an orange-buff facial disc. Its name comes from the tufts
of feathers that appear to be "horns" which are sometimes referred to
as "ear tufts" but have nothing to do with hearing at all.
Increasing day length stimulates the
mating urges each spring, although
the exact timing is also affected by the weather. As unbelievable as it
sounds, day length is not sensed through the bird’s eyes but by the
amount of light penetrating the skull directly into the brain,
according to Michael Caduto in his book Keepers of the Animals. The
pineal gland is a small pine-cone-shaped endocrine gland located near
the center of the brain, between the two hemispheres. In birds, the
pineal gland is light-sensitive and birds have thin skulls that
daylight can penetrate. In response, it produces hormones that initiate
breeding activities, as well as other behavior.
The great horned owl requires a very
long nesting season to raise its
chicks and must begin early if they are to be independent before winter
strikes again. By mid-January, a pair will have mated and set up
housekeeping in last year’s nest or perhaps claimed an old crow or
red-tailed hawk nest. It is not unusual to find a nest in late winter
where the female is covered with snow, protecting her eggs or even
chicks with her heavily feathered body.
In our woods, it is more common to
hear the distinctive conversations
of the barred owl, a medium-sized gray-brown owl streaked with white
horizontal barring on the chest and vertical barring on the belly. It
has a round head with a whitish/brown facial disk with dark brown trim.
The eyes are brown, and the beak is yellow and almost covered by
feathers.
The barred owl is a highly vocal bird
giving a loud and resounding
"hoo, hoo, too-HOO; hoo, hoo, too-HOO, oooooo" with the last syllable
dropping off noticeably. Other calls include "hoo-hoo, hoo-WAAAHH" and
"hoo-WAAAHHH" used in courtship. Mates will duet, but the male's voice
is deeper and mellower. They also many other noises including various
hoots, whines, and squeals, sometimes sounding like barking dogs,
whooping monkeys and even screaming or laughing human voices. Like some
other owl species, they will call in the daytime as well as at night
but unlike most others, both males and females hoot, both for mating
purposes and to define their territories.
As the nesting season approaches, the
male will chase after the female
giving a variety of hooting and screeching calls. When it comes close,
it displays by swaying back and forth, and raising its wings, while
sidling closer. Courtship feeding and mutual preening also occur. Pairs
mate for life and territories and a nest site is maintained for many
years, usually a cavity originally excavated by a woodpecker. The
female lays two to four round white eggs, one every two to three days.
Incubation begins with the first egg
laid so the resulting chicks hatch
in succession after about 4 weeks. If there is sufficient food, this
difference in age is no problem, but if hunting is poor, the smaller
chick or chicks often starve. When the young leave the nest, at about 4
weeks, they are not able to fly, but crawl out of the nest using their
beak and talons to sit on nearby branches and it is usually another
month or more before they are able to fly.
The parents care for the young for at
least 4 months, much longer than
most other owls and families remain loosely associated throughout the
summer before the young disperse. These owls are solitary in nature,
only staying with their mates during the nesting season but a pair will
maintain its territory for many years. If you are lucky enough to host
one, you will likely hear their haunting calls for many years to come.
---------------------------------------
January 11, 2011:
Squirrels in Winter
There seems to be an unusually large
number of squirrel tracks on the
trails this year, and Sunny is not the only one who finds these busy
little animals intriguing. All rodents, including squirrels, mice,
rats, porcupines, beavers, chipmunks, guinea pigs and voles and have
one characteristic in common. They have two continuously growing
incisors in the upper and lower jaws that must be kept short by
constant use. This continual wearing away keeps the teeth very sharp
and allows the animals to bite into hard nuts and wood, but if one is
prevented from gnawing, its teeth will grow so long that it will not be
able to close its mouth. Rodents are found in vast numbers on all
continents other than Antarctica: in fact, forty percent of all mammal
species are rodents.
Squirrels are especially interesting
because many of them have adapted
to life above ground in the trees. We have two species of tree
squirrels in southern Wisconsin – the grey and fox squirrel. It is
estimated that there are some 8,000,000 in the state, and although
about a quarter of these are harvested by hunters each year, they seem
to have no trouble keeping their population healthy.
The fox squirrel is the larger of the
two species, measuring about
20-22 inches of which almost half is tail, and weighing up to two
pounds. It has rusty grayish-brown upper parts and a yellowish-orange
belly and chest, although black and red phases also occur. The
gray squirrel averages several inches shorter and 6-8 ounces less, and
while normally a varied gray in color with a white chin, throat and
belly, it can also be all black or white. Both species have large bushy
tails that act as rudders when the animals jump from high places, as
warm covering during the winter, and as a means of communication with
other squirrels.
The squirrel has muscular hind legs
that allow it to leap more than 20
feet, and long hind feet that are double-jointed and equipped with
sharp claws to help it scramble head first down a tree trunk. If a
squirrel should fall, it can land safely from heights of 30 feet and
more, and we have often seen one just drop to the ground seemingly to
avoid having to climb down. When danger threatens, a squirrel will
sidle inconspicuously around the trunk of the tree, keeping just out of
sight. When it remains motionless against tree bark, it is very
difficult to see.
Squirrels mate from late January
through February and again in May
though early July. The male will vigorously defend his territory from
other males and then mate with every female he can catch. After
breeding, the female prepares a nest, which may be the winter den in a
tree cavity that she has lined with shredded bark and plant fibers, or
if an existing cavity is not available, she will build a round leaf
nest in the crotch of a tree, at least 25 feet above ground.
She weaves a platform of twigs about
two feet in diameter and then
packs it with damp leaves and moss to form a solid base. She then
erects walls and a roof of interwoven twigs and vines and fills them in
with leaves, moss, and twigs. Inside, she forms a nest cavity about six
to eight inches in diameter and lines it with shredded bark, grass, and
leaves. Although these nests look flimsy from the ground, they have
been found to be surprisingly warm and dry. During winter storms or
severe cold, the squirrel may not leave the nest for days but it does
not hibernate and feeds on stored nuts and acorns.
In the early days of our country,
hardwood forests were so extensive
that it is said that a squirrel could travel from Florida to Maine
without setting foot on the ground. This favorable habitat allowed
squirrel populations to reach very high levels at times. When the first
settlers arrived in Wisconsin, they found a huge population of
squirrels, and in fact, some communities actually paid bounties for
them to prevent crop damage. During this time there were enormous
squirrel emigrations, and in 1842, a gray squirrel migration lasted
four weeks and involved, according to one observer, nearly half a
billion squirrels. As forests were burned or cleared for agriculture,
squirrel population quickly declined.
During modern times, squirrel
emigrations have not been as spectacular,
but in 1964, millions of squirrels emigrated from the north of Georgia
to the south. Then, in 1968, a migration of squirrels occurred in much
of the eastern United States where some reports of the population went
as high as eighty million animals. In New York State, squirrel
road kill was a thousand times higher than usual, and an estimated one
hundred thousand drowned squirrels were pulled out of one reservoir. No
definitive explanation has ever been accepted for these occurrences,
but it has been generally believed that bumper nut crops were certainly
involved.
The unusual number of squirrel tracks
we are seeing in the snow may be
connected to the large acorn crop we had this past fall, but I doubt if
the population is high enough to cause an emigration. Then, too, I’m
sure that the hawks, raccoons, opossums, coyotes, foxes, and owls will
be alert and happy to take care of any surplus.
-----------------------------------
January 4, 2011: Bird Counts
The story is told that in past
centuries, it was tradition for the men
to take part in a "Side Hunt" on Christmas Day. Teams (sides) were
chosen and participants would go out with their guns to shoot as many
creatures as possible, and whichever group brought in the biggest pile
of feathered and furred quarry won. I don’t know how wide a practice it
was – or even if it really existed at all, as information on it is
rather sketchy – but the idea is appalling.
Presumably, it was this slaughter that
caused ornithologist Frank
Chapman, an early officer in the newly organized Audubon Society, to
propose a different holiday tradition around 1900 -- a "Christmas Bird
Census" -- that would count birds during the holidays rather than shoot
them. Twenty-seven dedicated birders located from Toronto, Ontario to
Pacific Grove, California accepted the challenge and tallied a total of
some 90 species. So began the Christmas Bird Count.
We are now nearing the completion of
the 111th count, which began on
Tuesday, December 14, 2010 and will end on Wednesday, January 5, 2011.
Tens of thousands of volunteers throughout the Americas have taken part
in this effort that has become a family tradition for many. Families
and students, birders and scientists, armed with binoculars, bird
guides and checklists go out each year regardless of the weather,
reporting their sightings to be tallied by the Audubon Society.
Scientists and bird enthusiasts can
learn a lot by knowing where the
birds are and how they seem to be faring. Bird populations are dynamic
and constantly changing and no single scientist or team of scientists
could hope to document the complex distribution and movements of so
many species in such a short time. The declining bird populations
reflect growing threats to many bird species resulting from habitat
loss and fragmentation caused by development and human recreation.
Other contributing factors include competition from non-native species,
diseases such as the West Nile virus, collisions with vehicles and
structures, and weather-related injury.
On the other hand, it is encouraging
to discover that the numbers in
some species have rebounded as we have learned what was causing their
problems and been able to alleviate them. The bald eagle and the
peregrine falcon are no longer considered endangered and there are
other birds whose populations have also increased. These indicate that
we can make a difference in some cases, despite the generally
discouraging statistics.
It is too late this year to take part
in the Christmas count but you do
have an alternative opportunity. The 14th annual Great Backyard Bird
Count, a four-day event, will be held from February 18 - 21, 2011, and
anyone can participate, from novice bird watchers to experts. Each will
be asked to count any birds seen during the four-day period and to
record the highest number of birds of each species seen together at any
one time. To report the counts, there is an online checklist at the
Great Backyard Bird Count website. It’s free, fun, and easy -- and it
doesn't matter whether you report the five species coming to your
backyard feeder or the 75 species you see during a day's outing at a
wildlife refuge.
Each checklist submitted helps
researchers at the Cornell Lab of
Ornithology and the National Audubon Society to learn more about how
the birds are doing -- and hopefully how to protect them and the
environment we share. Last year, participants turned in more than
97,200 checklists online, creating the continent's largest
instantaneous snapshot of bird populations ever recorded. As the count
progresses, anyone with Internet access can explore what is being
reported from his or her own town or anywhere in the United States and
Canada. It is also possible to compare this year's numbers with those
from previous years.
A third opportunity is still available
in the 2010-11 FeederWatch,
(information also available on line) although this will cost you $15 to
cover materials, staff support, web design, data analysis, and a
year-end report. This project began November 13, but there's still time
to join as it runs through April 8, 2011. You will be asked to count
any birds that appear in your yard to take advantage of something that
you have provided (food, water or natural plantings). Again, for each
species, you will report only the highest number of individuals that
you have in view at one time so that you will avoid counting the same
bird more than once.
The U.S. Fish and Wildlife Service
reports that one in every five
Americans is an active birdwatcher, and while most just feed in their
own backyards, others travel around the world to seek out new species.
Bird watching is a fun and educational hobby that anyone can enjoy with
just an identification guide and a pair of binoculars. No matter where
you live, there are birds around, and adding a bird feeder or birdbath
to your yard can help bring the birds to you. If you truly want to
pursue this hobby, though, you should to keep some records on the birds
that you see. Start making a list (birders call it their life list) to
record your sightings, and then add your observations to those of
others around the country by joining one of the “Counts”.
----------------------------------------------------------
December 28, 2010: Blue Birds: Birds that aren't blue!
Fifteen, sixteen, seventeen… The blue jay sitting on the edge of into
the seed basket dipped its beak into the pile, each time coming up with
a fat sunflower seed and then tipping back its head and swallowing it.
At the count of twenty I thought surely the bird must be full to the
brim, but it only jumped down into the center of the basket and
continued without a break. Hard as it might be to believe, that bird
ingested 60 seeds before flying off, answering the question as to why
the seed supply always seemed in need of replenishing.
Carter Johnson and Curtis Adkisson, in their article, Airlifting the
Oaks in the Natural History Magazine, studied the oak planting
abilities of eastern blue jays. They kept track of 50 jays and found
that they gathered and cached 150,000 acorns in 28 days, about 110
acorns per day for each bird. Blue jays are energetic hoarders, storing
acorns and other booty in cracks and crevices of tree trunks or in
loose soil where many that were not later eaten would subsequently
sprout.
A blue jay can carry up to five acorns (or evidently 60 sunflower
seeds) at once by swallowing and carrying them in the upper part of its
large, expandable esophagus. The hoard is then regurgitated at chosen
storage sites around the area. Blue jays are members of the crow family
and are highly intelligent with good memories, and they usually
retrieve most of the stored material. They eat mostly acorns, nuts, and
seeds with a few insects and small vertebrates thrown in, and are not
above feasting on eggs and nestlings of other bird species if
available. Blue Jays are adaptable and will take advantage of almost
any food source, eagerly coming to backyard bird
feeders.
It is always hard to remember that the bright blue on these birds is
produced by a trick of the light, rather than an actual pigment. Most
other bird feathers get their brown, black, and gray colors from
melanin, the same dark biological pigment that affects human skin, or
carotene that shows as yellows, oranges and reds. Both kinds of pigment
act to absorb certain wavelengths of light and reflect the rest,
causing them to appear to our eyes as color.
A blue jay's feathers do have melanin but it is below the surface under
a layer of bubble-like cells. These bubbles reflect and scatter blue
light waves, while the melanin absorbs the other colors of light. That
is why the blue jay's feathers look blue in sunlight but a darker
gray-blue in the shade, as the melanin is more visible. White is also a
structural color; that is, we see feathers as white when their
structure reflects back to our eyes the full range of the light
wavelengths that strike them. When a white feather is observed under a
powerful microscope, the surface resembles cut glass or snow. It lacks
melanin and contains many more air bubbles than does a blue feather.
In contrast to the melanin that can be manufactured in their bodies,
birds must obtain red, orange or yellow carotenoid pigments from the
seeds and berries that they eat. These pigments are manufactured only
by plants, and when the bird acquires them through its food, they are
dissolved in fat globules and then deposited into their growing
feathers. In the 1800s, this process led to the captivity of untold
numbers of the beautiful red bird we call the northern cardinal. It was
found that these colorful birds would adapt readily to life in an
aviary if introduced as nestlings, and would sing several months of the
year.
They became much-sought-after cage birds, and thousands were trapped in
the south in the winter and sent to northern markets, and thousands
more were sent to Europe. Cardinals are noted for their loud, clear
whistled songs, and even the females will sometimes join their mates in
singing. These songsters were highly valued, but it was soon observed
that their colors faded in captivity and it was only later that it was
found that this was due to the foods they were routinely fed. This
trade was halted, fortunately, with the passage of the Migratory Bird
Treaty Act of 1918.
The cardinal was originally found only in the southeast parts of the
country, but its range has expanded northward in the last 100 years. In
1886 it was seen only occasionally north of the Ohio River but by 1895
it had reached the Great Lakes and by 1910, it was discovered in
southern Ontario. Since the food supply is the major factor in winter
survival for birds, it may be our hobby of backyard feeding that has
allowed it to survive our Wisconsin winters and grace our lawns and
trees.
The image of a northern cardinal perched upon a snowy branch is so
striking that it is used extensively on Christmas cards, calendars,
clothing and all sorts of holiday decorations; in fact, I would be
willing to bet that I am not the only one who has exclaimed about the
beauty of such a sight outside the window this week. Add to that the
blue of the jays, the gold of the finches, and the bobbing red heads of
the woodpeckers, and winter loses much of its depressing drabness. A
happy new year to you all!
-----------------------------------------------------
December 21, 2010: The Chickadee: A
Christmas Bird
It seems strange that chickadees can
be found on so many of the
decorations offered for the Christmas season. Certainly they grace
numerous holiday cards, but you can also find them on tree ornaments,
clothing, tree skirts, pillows, throws, stockings, and who knows what
else? There are perhaps more chickadees than reindeer!
Why should this little bird be so
popular? It is almost universally
considered endearing—probably because it is almost cartoon-like with
its oversized round head, bright black eyes, tiny body, and its
curiosity about everything, including us. The chickadee’s black cap and
bib, white cheeks, gray back, wings, and tail, and whitish underside
with buffy sides are distinctive. If you feed the birds, you probably
have discovered that it watches you constantly from a nearby perch and
is the first to return to a feeder after you fill it.
The chickadee is a part of the
Titmouse family that is widely
distributed in North America from the Atlantic Ocean to the Pacific, in
England, and across Europe. There are five species in North America:
the black capped chickadee which makes its home to the north, the
chestnut backed chickadee found in the Pacific Northwest, the Carolina
chickadee which is found in the southeast, the mountain chickadee found
in the west, and the Mexican chickadee found in Arizona, New Mexico and
mountainous areas of Mexico.
Chickadees are usually seen in pairs
or small groups. When nesting is
over and the young fledge, they often form small flocks of up to a
dozen birds that will roost and forage together until the next mating
season. Finding food in the winter is often tough, and hunting together
seems to increase their chances for success. This group concept also
helps as a predator defense system with many pairs of eyes to look for
and voices to warn of approaching danger.
If you have chickadees at your feeders
you have probably heard their
many calls and even conversations, as they are seldom silent. Thirteen
distinct types of vocalizations have been classified, many of which are
complex and can communicate different types of information. The song is
a simple, clear whistle of two and sometimes three notes, the second
and third a step lower than the first, but the most familiar call is
the familiar “chick-a-dee-dee-dee” which gave this bird its name.
This call may sound simple to our ears
but is astonishingly complex. It
consists of up to four distinct units that can be arranged in different
patterns to communicate information. A recent study of the call showed
that the number of “dees” usually indicated the level of threat from a
nearby predator. It was found that alarm calls triggered by small,
dangerous raptors had a shorter interval between chick and dee and
tended to have extra dees, usually averaging four instead of two. In
one case, a warning call about a pygmy owl – a prime threat to
chickadees – contained 23 dees.
“Black-capped Chickadees have a
wonderful assortment of adaptations for
the winter,” writes biologist Susan Smith, who has long studied them.
“Carefully hidden food items, dense winter coats, specially selected
winter roost cavities, and perhaps most remarkable of all, the ability
to go into nightly hypothermia, thus conserving large amounts of
energy, greatly increases the chances of survival,” she said. This
lowers the chickadee’s body temperature down to about 12 or 15 degrees
(F.) below their normal daytime temperature of 108 degrees (F.), and
allows the bird to reduce its heat loss by about 25%.
The chickadee is largely an insect
eater and spends much of its time
gleaning insects, eggs and larvae as it clings to a tree trunk, twig or
branch. As the temperature drops and when such food becomes scarce, it
switches to pine, birch, and weed seeds and any berries it can find. It
loves sunflower seeds, peanut kernels, peanut butter mixes and suet and
becomes a regular and eager visitor to any feeder it can discover that
offers them. The bird will typically take one seed, fly away and perch
nearby to eat it or else hide it for later use. Often the flock will
settle nearby, each member waiting its turn to grab a seed, and
conversing about the situation. With a little patience, some of
the bolder birds will even accept seed from a person's hand.
All of us at Timbergreen Farm send you
our best wishes for a joyous
holiday season and hope you will spend part of it outdoors enjoying the
chickadees and other wildlife, as well as the beauty of our Wisconsin
countryside.
---------------------------------------------------
December 14, 2010: A Walk in the Snow
A walk in the woods is a very
different experience in contrast to just
a few short weeks ago. Then the views were splashed with gold,
maroon, and scarlet but now all is black and white. Only a family of
crows harassing a passing hawk across the hill breaks the silence—a
radical change from the noisy crunch of dried leaves underfoot and the
conversations of the migrating birds as they moved through the tree
branches or flew overhead in loose clouds or ever-changing formations.
Snow is an important feature of the
winter landscape. Mice and other
small mammals build complex tunnel systems beneath the surface to link
their burrows with food storage sites that protect them from the worst
cold and many predators. The air spaces between the snow crystals in a
mantle of loosely packed snow serve as insulation for the ground below
(one scientist reported that ten inches of fresh snow is approximately
equal to a six-inch-layer of fiberglass insulation) so while a deep
snow layer may have its upper surface drop to extremely cold
temperatures, the ground temperature beneath may remain around
freezing. All the small creatures and plants benefit.
Fresh snow is basically a blanket of
crystals that reflects the natural
white light that hits them but sometimes sparkles in red, blue and
yellow. Within the layer of snow there are many different
surfaces reflecting in many different angles and the light bounces all
over and then scatters back out of the snow making it appear white.
However, cold, dry nights can squeeze moisture out of the air and the
top layer of snowflakes, causing it to crystallize into faceted
patterns similar to a diamond. This can bend and split light into its
rainbow of wavelengths the way a prism does, sometimes creating
brilliant colors.
Snow also allows us to see evidences
of the variety of creatures that
live and move around in the winter woods. After hunters have taken
their harvest of deer (I read that in Sauk County alone 6000 were
killed), one would think that these animals would be scarce, but their
tracks prove that such is not the case. Now we can follow their
movements as easily as Sunny does, and our eyes can see what her nose
tells her.
Deer may be the most obvious animals
but there are other signs as well.
A coyote has left its scat in the middle of our trail—a clear signal to
other coyotes that this is its territory. A dead shrew lying on the
snow may have been attacked by a predator that quickly discovered that
it wouldn’t make a good meal and spit it out. Squirrels hopped from
tree to tree, leaving their paired tracks as they went. They also left
evidences of digging for buried acorns or other nuts, scattering dirt
and dead leaves in their wake. A flock of turkeys passed by—their
tracks leading right down to the bird feeders in the yard.
Tracks of a variety of mice and shrews
formed highways between shrub
stems. Most hopped across the surface, sometimes leaving clear tail
marks, while a few tunneled just below, causing the snow to lift into
ridges. These soon collapsed but the animal was long gone, leaving just
an open furrow that ran from the exit hole to where it reentered its
under-snow world. We noticed one patch of little bluestem grass whose
seeds had become accessible due to the deep snow that was now packed
down by tiny feet.
Other tracks are also in evidence:
along the path, clumps of the white
stuff fell from overhanging branches leaving a series of irregular
marks; in another spot a strange arc pattern was formed by a heavy
grass stem swinging back and forth in the wind; a long groove showed
where a snowball rolled down the slope, perhaps kicked up by a passing
animal. Sometimes these were hard to distinguish from those made by
animals.
Beautiful as the snow is on the trail,
it makes hiking much more
difficult, particularly going up and down the hillsides. For one thing,
I am encumbered with several pounds of extra clothing including heavy
boots. Then, too, the footing is uncertain, as obstacles are now hidden
and the surface is slippery. I carry a staff, but still stumble and
slide as I make my way along. Paths that I recently climbed with only a
few stops to catch a breath now require longer periods of recuperation
before making my way to the ridge. More snow is on the way so
Sunny and I make our way homeward, looking forward to a warm cup of tea
while Sunny chews the ice balls from between her toes and dreams of
future excursions.
----------------------------------------------------
December 7, 2010: Beware of the
Hawks
When we think of meat-eaters in the
wild, it is usually animals that
come to mind—wolves, coyotes, and cats of all kinds—but the great
majority are actually birds. Many of these seem relatively harmless to
us such as robins and bluebirds, the warblers, even woodpeckers, but
there are some species that are quite fierce.
Hawks are carnivores that belong to
the category of birds known as
raptors -- birds of prey. They have strong, hooked beaks and their
claws, or talons, are long, curved and very sharp. Prey is killed with
the long talons and, if it is too large to swallow whole, it is torn to
bite-sized pieces with the beak. Based on general body shape and flight
habits, hawks are classified into three different groups: the
accipiters, the falcons and the buteos.
The sharp-shinned hawk, the Cooper's
hawk, the goshawk and the Northern
harrier are accipiters. They have long tails and short, rounded wings
that enable them to dart through and around trees in pursuit of other
birds, their principal prey. Typically, they fly low with a series of
rapid wing beats followed by a brief period of sailing, then another
series of wing beats. Accipiters are usually found in brush and
timbered areas.
One of these may find that your bird
feeder an excellent place to hunt,
as the small birds that are attracted to your seeds and suet are its
favorite food. It doesn’t take long for the chickadees and sparrows to
realize that it is a dangerous place to visit, however, and they look
for safer spots to feed until the hawk gives up and moves on. If
your feeders seem unusually quiet, look about in the nearby trees for a
hawk on the prowl.
Much of what we know about our winter
birds comes from Project Feeder
Watch, an undertaking of the Cornell Lab of Ornithology in Ithaca,
NY. Participants all over the continent count the birds they see
at their feeders from November through early April and send in their
data to scientists who track broad scale movements of winter bird
populations and long-term trends in bird distribution and abundance.
Each reporter contributes $15 to join, making Project FeederWatch
largely self-sustaining, and birders everywhere are urged to take part.
One of their conclusions is that
almost a third of all predation deaths
at feeders are caused by sharp-shinned hawks.
To survive, these birds must capture
and eat an average of one bird per
day, and that is a difficult feat as watchers report that only one
strike in three is successful. They have especially long middle toes
and large eyes, adaptations that help them to capture the small, agile
birds that make up almost their entire diet. Both the Cooper’s and
sharp-shinned have been known to cache uneaten prey in trees for later
use.
Falcons, on the other hand, prefer
open country. They include the
peregrine falcon (often called the duck hawk), the merlin (called the
pigeon hawk), and the little American kestrel, (called the sparrow
hawk). Falcons have streamlined bodies, long, pointed wings and long
tails. A series of strong, rapid wing beats gives them extremely fast
flight in open country, and their swiftness allows them to overtake and
capture other birds on the wing. The American kestrel is the smallest
of our hawks and feeds mainly on mice and insects. It is the only one
of the falcons that hovers over its intended prey and the only one that
often stays year around. Because of its habitat and range, it is also
the only falcon or accipiter that most people are likely to see.
The buteos are sometimes called
buzzard hawks and are the largest of
the hawks. They are the broad-winged, broad-tailed soaring birds that
are often seen circling high in the air or perching in dead trees or on
telephone or power poles along the road. The most common is the
red-tailed that can be observed all year long. The broad-winged and
red-shouldered are relatively rare and migrate south for the winter,
while the rough-legged hawk is a northern nester and can be seen only
in the winter, usually sitting on a perch overlooking an open
field. These hawks are much too big and heavy to be very
successful at catching birds and most of their diet is made up of
rodents. They will attack pheasants and other ground-nesting birds,
however, and red-tails find the young of these birds particularly easy
prey in the early summer.
Since the beginning of recorded
history, birds of prey have been both
hated and revered. The sport of falconry -- using raptors as hunting
aids -- has been practiced in Asia and Egypt for thousands of years and
The North American Falconers Association still holds an annual meet
attended by dedicated birders from around the world. Yet until recent
years, birds of prey have also been ruthlessly trapped and shot because
they have been accused of attacking game and domesticated animals. Now
all are protected by federal law and it is better understood that they
hold an important place in the balance of nature, as do all predators.
---------------------------------------------------
November 30, 2010: Nasty Natives
Now that the vegetable and wildflower
gardens are cleaned up and tucked
in for the winter, we have turned our attention to clearing and
treating areas of nuisance scrub growth. The trails that allow us to
hike around and across our hillsides and valleys are continually
encroached upon by a variety of spreading plants and it is a
never-ending fight to keep them in check. We know that many of our
now-wooded areas were once savanna, where scattered white and bur oaks
grew on land carpeted with prairie grasses and flowers, but the
repression of the once common wild fires and later the end of cattle
grazing in the woods has allowed other trees and shrubs to invade and
squeeze out all but the most persistent grassland and woodland plants
in much of the area.
It is common to blame alien
introductions for the problem, but many of
the invasive plants are robust natives that persist and thrive under
conditions where other more retiring plants may be overwhelmed. Most
are introduced as seeds carried in by the wind or by a wild passerby,
but once started, many spread by sending out adventurous rhizomes in
all directions. (A rhizome is a specialized stem that grows
horizontally just below the soil surface and puts up new growth and
ultimately a new plant at each node.)
Northern prickly ash has always been
one of the most troublesome,
partly because of its nasty thorns, but also because it spreads so
enthusiastically. When the soil is soft, it is sometimes possible to
pull out a long series of young sprouts, each attached to its neighbor.
In time each shoot would grow into a smah tree from 10 to 12 feet
high, with compound leaves made up of from 5 to 11 leaflets. The
greenish-yellow flowers appear in April before the leaves appear and
the fruits are clusters of dark red, berry-like capsules, each
containing one or more shiny black seeds. Both the berries and the bark
were traditional remedies for indigestion and toothache for early
people, and the wild creatures eat them and distribute the indigestible
seeds wherever they go.
Another pest is the sumac that is
present in both the staghorn and the
smooth varieties and which often can only be told apart only by the
long hairs on the twigs and fruits on the staghorn. Sumac rarely
reaches over 10 feet in height but it forms spreading colonies of
multi-stemmed clones. Their twigs are coarse and angular, and they bear
compound leaves that turn a brilliant red in fall. On female clones,
clusters of red fruit develop at the end of the stems in late summer
and persist into winter, each fruit containing a single seed. This
woody invader will crowd out other plants, and although it doesn’t have
thorns like the prickly ash, it seems determined to re-sprout and has
proved very difficult to control.
A third group of rhizome-growing
plants that we sometimes view with
dismay is made up of red and black raspberries and blackberries. When
they grow on good sites (which doesn’t seem to happen very often), they
produce delicious fruit and we pick and eat them with great pleasure.
Generally, however, the patches around the farm produce few berries and
consist only of long thorny arching branches that seem determined to
wrap around and trap any intruder.
Raspberry canes generally live 2 years
and may grow five or six feet
long. Purplish-red with a white bloom and hooked prickles, they not
only spread by rhizomes but readily root at the tips and form new
plants wherever they contact the ground. Blackberry canes tend to be
more coarse, and sometimes grow as long as eight feet. When these
thorny stalks are draped with the numerous climbing branches of the
many wild grapevines that cling to everything they touch with curly
tendrils, you have an almost impenetrable thicket. It must be painfully
cut out plant by plant, rooted out when possible and painted with a
brush killer when not.
Wild grapes are perennial, woody vines
with dark gray-brown bark that
is sloughed off in long, narrow strips. They grow thicker and higher
than most other native vines and may reach more than eighty feet into
the canopy, clinging by means of tendrils which coil themselves around
tree limbs and twigs. The leaves of grapes could be described as
somewhat maple-like and are fairly large, often six to eight inches
wide. Their tiny flowers are greenish-white and are borne in large
clusters that hang from a main stalk opposite a leaf. The fruit is
small and sour but is an important wildlife food, and makes good jam
for humans, as well. The major problem with them is that if they can’t
find a tree to climb, their many branches spread across the ground,
putting down roots and new sprouts as they travel and forming
bothersome barriers.
In addition to these constantly
spreading plants are other natives that
we also try to discourage—poison ivy, grey and red osier dogwoods, red
cedar and box elder trees, to name only a few. And we won’t even
mention all of the non-native species that have invaded our area. It is
a never-ending battle, and perhaps one that we are sure to lose, but we
fight on and enjoy our time in the out-of-doors as we work.
--------------------------------------------------
November 23, 2010: All About Moss
While making our way gingerly through a patch of prickly ash below the
rock cap on the hill, friend Cindy spotted an unusual sight for the
middle of November. There, clinging to the surface of one of the
sandstone rocks was a blooming hair-bell. These delicate blue blossoms
are common in May and June on the ridge prairie remnants but hardly
expected with winter right around the corner. The fact that it had
taken root on bare rock in the shade was also strange, and even more
unusual that it could produce a cluster of flowers.
There are other green plants to see in the woods, however, that we
seldom notice until all the more dominant species have died or gone
dormant for the winter. Many of these are mosses, very simple
growths that are notable because they lack conventional roots, stems,
and leaves. They are thought to have been the first green land plants
to develop during the evolutionary process and have proved so
successful that they have not changed throughout the millennia.
In northern latitudes, look for mosses on the north side of trees and
rocks (although south-side exposures are sometimes found). South of the
equator the reverse is true and it is assumed the reason for both
locations is that the sun-facing side of trees dries out more quickly.
In deep forests where sunlight does not penetrate, mosses grow equally
well on all sides of the tree trunk.
Even though they lack the internal structures that carry sap and
nutrients up and down the tissues of most other plants, moss is present
all around the globe wherever there is sufficient moisture. The small,
soft plants seldom grow over four inches tall, and lack a waxy covering
on their “leaves” to prevent water loss. They commonly grow close
together in clumps or mats in damp shady locations and need liquid
water to complete fertilization.
The life of a moss plant starts from a spore, a reproductive cell that
is different from a seed in that it contains little stored food and has
only one set of chromosomes instead of a paired set. The spore
germinates to produce a mass of thread-like filaments that look like a
thin green felt, and may grow on damp soil or rocks. From this mat
emerges a clump of shoots that resemble stems covered with tiny leaves.
Reproduction in mosses seems complicated. In the spring, the moss
female organ emerges as a small flask-shaped clump of cells that grows
from the tip of the shoot. At the same time capsules containing the
male sperm emerge and are held up on the top of stalk-like structures.
When it rains, sperm are able to swim down their stalks to the female
organs where fertilization occurs and a spore-plant begins to grow out
of the top of each shoot. This consists of three structures—a foot that
anchors it and helps it to absorb water and nutrients, a long erect
stalk, and a pod-like capsule at the end. Within the capsule,
spore-producing cells with two sets of chromosomes split to form
reproductive spores, from which the cycle can start again.
There are hundreds of species of mosses and among the most conspicuous
here at the farm is the hair-cap moss with erect stems and densely
hairy caps that give them their name. They have pointed “leaves”
arranged spirally around their stems and are often found in fairly
dense colonies.
Farther north in Wisconsin, large deep colonies of peat moss are
common. This is the fundamental species of bogs, forming and acidifying
much of the habitat in which other plants can grow, its stems held
upright by the close growth of its neighbors. Sphagnum is by far the
most economically important of the peats and is used extensively as a
soil amendment, packing material and fuel.
Unrelated plants are also called “moss” such as club moss, a ground
hugging evergreen perennial plant with dense spirals of yellow green
leaves; moss rose, another name for the garden creeping phlox;
carageen, is a type of algae sometimes used in health foods; reindeer
moss, which is actually a lichen; and Spanish moss, a parasite that
grows in long streamers and is often seen in the southern sections of
the country. Many of these also reproduce by spores but have
other characteristics that set them apart. We may not see these
fascinating plants in our woods, but others are waiting to be
discovered.
----------------------------------------------------------
November 16, 2010: Bucks,
Pileated, and Witch-hazel
The woods may seem quiet as November
creeps into winter but that does
not mean there is nothing to see. A bald eagle circles over the field,
watching for the slightest movement that might mean an unwary mouse is
feeding in a patch of weeds. Sunny flushes a deer and sends it leaping
across the trail, although it is more of a game for both of them as she
has not the slightest chance of catching it. The sun is low in the
south, even at midday, but it will sink even more before the Solstice
on December 21st.
We can tell that the whitetail buck
deer are vying for mates, as they
have marked numerous young trees and patches of ground to give notice
to potential mates and rivals of their presence. Their antlers have
reached full size and the initial cartilage that allowed them to
accomplish such fast growth has mineralized. Then the skin covering
that supplied the new appendages with oxygen and nutrients has sloughed
off and the deer have polished their hard surfaces on the fragile tree
bark. The bucks have also scraped spots on the trails with their front
hooves to expose bare earth where they urinate to leave their scent.
A riddled aspen stump has left
evidence that a pileated woodpecker has
been feeding. Chips litter the ground beneath it and the rotting wood
was no match for that large bird’s formidable beak. Other woodpecker
holes can also be seen higher in the trees and natural cavities that
have been enlarged, but none rival those of the pileated.
It is true that most of the plants are
dormant now but a few continue
to carry on until heavy freezes will finally bring all growth to a
halt. The stalks of many of the blackberries still hold some of their
mahogany and purple leaves, and there are scattered patches of light
green where greenbrier has spread over some of the underbrush. This
native vine has two varieties here at the farm—one that has small dried
berries on short stalks at leaf nodes while the other has 2-inch tight
purple berry clusters hanging from its strong stems.
Perhaps the biggest surprise in the
woods, however, is the witch-hazel.
We have a steadily expanding patch of this large shrub in one spot on
the back ridge and visiting that area is a late fall tradition. While
you might assume that the plant historically had some connection with a
woman with magical powers, the name “witch” actually has its origins in
Middle English wiche, from the Old English wice, meaning "pliant" or
"bendable". It seems that twigs of the shrub have long been used as
divining rods, and this function gave it the name.
There is nothing very noticeable about
witch-hazel for most of the year
but it has slightly aromatic branches and leaves, and an extract of the
bark has long been a remedy for numerous ills. I never would have
identified it from its form or wave-toothed leaves had it not been for
the bright yellow flowers it produces at this time when little else is
showing any color. After all the other trees and shrubs have shed
their leaves and are standing bare and brown, this plant comes into
bloom, displaying its one-inch rather scraggly looking blossoms.
This is not the only thing strange
about witch-hazel, however, as
fruit, flowers, and next year's leaf buds all appear at the same time—a
rarity among trees. Each flower has four slender petals and the fruit
is a capsule containing two glossy black seeds. Last year’s seed pods
still hang on the branches ready and waiting and soon will pop open,
flinging the seeds over a wide area. (Few plants distribute their seeds
at the same time they open their blossoms but the witch-hazel does just
that.) Then, late next autumn, this year’s capsule will split
explosively, ejecting the seeds with sufficient force to fly for
distances of up to 30 feet.
Exploring the woods has been lovely
this fall, but it is likely that we
will soon have to don heavy parkas, boots, and mittens when Sunny
demands a walk. Snow is now being mentioned in the weather forecasts
but that only brings a new interest to any excursions, as tracks of all
kinds prove creatures seldom seen are out and active. We keep
looking for a bear but in the meantime there is always something
interesting to look for...
November 9, 2010: Winter Birds
A few weeks ago the woods were
atwitter with little birds, but now as
one walks the trails, they seem empty and quiet. Most of the local
nesters have taken flight toward the south to escape the winter, and
those that remain are busy storing food for the difficult months to
come. Many woodpeckers stay, as do the goldfinches, chickadees,
nuthatches, cardinals, blue jays, English sparrows, and red-tails;
still we miss the hummingbirds, most of the thrushes and finches, and
all the warblers.
One species that we always welcome at
this time of the year, however,
is the dark-eyed junco. These rather non-descript birds make up the
small flocks that fly up as you drive the country roads, flashing their
white outer tail feathers. Otherwise they are mostly gray or brown with
white bellies and could be mistaken for just another sparrow. You can
also hear their very high-pitched chipping calls as they converse in
the underbrush.
Juncos are one of the strange bird
types that consider Wisconsin to be
the “southland”, and arrive here in October and stay until March or
April. They breed among the evergreens or mixed forest areas in Canada,
building their nests in cup-shaped depressions on the ground and lining
them with fine grasses and hair. They mainly eat insects and seeds,
foraging on the ground, but leave their frigid homes and are happy to
come here and take advantage of the feeders that many of us put out.
Another new arrival that we sometimes
see at our feeder is the
red-breasted nuthatch, a cousin of our familiar white-breasted nuthatch
that is a year round resident in our area. The two act much alike,
climbing up and down tree trunks headfirst and poking for insects in
the bark, but the red-breasted is a bit smaller and has reddish
underparts and a white stripe above each eye. Its call is similar but
higher-pitched than that of the white-breasted, and some have likened
it to a tin trumpet.
The red-breasted prefers mature, wet,
coniferous forests and breeds all
across Canada but can sometimes be found in the northeastern and
western United States. It excavates a nest in dead wood, typically
close to the ground and often applies sticky conifer resin to the
entrance of the hole that may help to keep out predators or
competitors. It is also known to hoard excess food by wedging nuts into
bark and then hammering them in with its bill.
There are several other winter
visitors to southern Wisconsin feeders
that we seldom see here at the farm: the American tree sparrow, with
its rusty crown and a black splotch on its plain breast; the purple
finch, a dull rose-red finch with stripes on its sides and belly; the
pine siskin, a small streaked finch with a flash of yellow in its wings
and tail; the common redpoll, an even smaller finch with a rosy breast,
red crown and black chin; and the evening grosbeak, a much larger bird
with a dull, gold body with black on its wings and a short tail.
The snow bunting, horned lark, and
rough legged hawk do not seem to
come to our yards but can sometimes be seen along the roads after the
snow covers the ground. The snow bunting is a mostly white bird that
breeds on the arctic tundra and treeless moors, while the horned lark
also comes down from the high Arctic and northernmost Europe and Asia.
It is mainly brown-grey above and pale below, with a striking black and
yellow face pattern. The summer male has black "horns", which give this
species its name.
A rough legged hawk has hunted along
Neuheisel Road for a number of
winters and we always look for it to be sitting atop one of the power
poles there. It, too, nests in Arctic tundra and taiga regions
and evidently finds the winter months much more pleasant in the river
valley than on its breeding grounds. Its distinguishing marks are its
white tail with a dark terminal band, as well as the feathered legs
from which it gets its name. We spied it for the first time this
weekend and will be watching for it on its favorite station each time
we go into town, happy that it has made it through another year.
Looking for and identifying these and
other visitors makes up somewhat
for the absence of our summer regulars and adds variety to the bird
lists that some of us keep. Keep your bird books
handy!
A few weeks ago the woods were atwitter with little birds, but now as
one walks the trails, they seem empty and quiet. Most of the local
nesters have taken flight toward the south to escape the winter, and
those that remain are busy storing food for the difficult months to
come. Many woodpeckers stay, as do the goldfinches, chickadees,
nuthatches, cardinals, blue jays, English sparrows, and red-tails;
still we miss the hummingbirds, most of the thrushes and finches, and
all the warblers.
One species that we always welcome at this time of the year, however,
is the dark-eyed junco. These rather non-descript birds make up the
small flocks that fly up as you drive the country roads, flashing their
white outer tail feathers. Otherwise they are mostly gray or brown with
white bellies and could be mistaken for just another sparrow. You can
also hear their very high-pitched chipping calls as they converse in
the underbrush.
Juncos are one of the strange bird types that consider Wisconsin to be
the “southland”, and arrive here in October and stay until March or
April. They breed among the evergreens or mixed forest areas in Canada,
building their nests in cup-shaped depressions on the ground and lining
them with fine grasses and hair. They mainly eat insects and seeds,
foraging on the ground, but leave their frigid homes and are happy to
come here and take advantage of the feeders that many of us put out.
Another new arrival that we sometimes see at our feeder is the
red-breasted nuthatch, a cousin of our familiar white-breasted nuthatch
that is a year round resident in our area. The two act much alike,
climbing up and down tree trunks headfirst and poking for insects in
the bark, but the red-breasted is a bit smaller and has reddish
underparts and a white stripe above each eye. Its call is similar but
higher-pitched than that of the white-breasted, and some have likened
it to a tin trumpet.
The red-breasted prefers mature, wet, coniferous forests and breeds all
across Canada but can sometimes be found in the northeastern and
western United States. It excavates a nest in dead wood, typically
close to the ground and often applies sticky conifer resin to the
entrance of the hole that may help to keep out predators or
competitors. It is also known to hoard excess food by wedging nuts into
bark and then hammering them in with its bill.
There are several other winter visitors to southern Wisconsin feeders
that we seldom see here at the farm: the American tree sparrow, with
its rusty crown and a black splotch on its plain breast; the purple
finch, a dull rose-red finch with stripes on its sides and belly; the
pine siskin, a small streaked finch with a flash of yellow in its wings
and tail; the common redpoll, an even smaller finch with a rosy breast,
red crown and black chin; and the evening grosbeak, a much larger bird
with a dull, gold body with black on its wings and a short tail.
The snow bunting, horned lark, and rough legged hawk do not seem to
come to our yards but can sometimes be seen along the roads after the
snow covers the ground. The snow bunting is a mostly white bird that
breeds on the arctic tundra and treeless moors, while the horned lark
also comes down from the high Arctic and northernmost Europe and Asia.
It is mainly brown-grey above and pale below, with a striking black and
yellow face pattern. The summer male has black "horns", which give this
species its name.
A rough legged hawk has hunted along Neuheisel Road for a number of
winters and we always look for it to be sitting atop one of the power
poles there. It, too, nests in Arctic tundra and taiga regions
and evidently finds the winter months much more pleasant in the river
valley than on its breeding grounds. Its distinguishing marks are its
white tail with a dark terminal band, as well as the feathered legs
from which it gets its name. We spied it for the first time this
weekend and will be watching for it on its favorite station each time
we go into town, happy that it has made it through another year.
Looking for and identifying these and other visitors makes up somewhat
for the absence of our summer regulars and adds variety to the bird
lists that some of us keep. Keep your bird books
handy!
--------------------------------------------
November 2, 2010: What is a
"Mast" Year?
It is hard to walk any of our woodland
trails without crushing some of
the acorns underfoot that presently carpet them. It has proved to be an
unusually prolific seeding year (traditionally called a mast year) for
the oaks, and all of the wildlife will benefit. The term "mast" comes
from the Old English word "maest", meaning the nuts of forest trees
that have accumulated on the ground, especially those used as food for
fattening domestic pigs. Acorns are a valuable though often unreliable
source of food for more than 180 different kinds of birds and mammals
such as squirrels, blue jays, crows, woodpeckers, deer, turkey, quail,
mice, chipmunks, ducks, and raccoons, to say nothing of insects and
other invertebrates.
Acorns start out as a few cells at the
tip of the oak branch. The end
of each twig can have flowers of both sexes as well as new leaves. With
mild, sunny weather in March or April, some cells swell into a
vase-shaped ovary topped with tiny, sticky, fuzzy knob (the pistil),
ready to capture any wind-blown pollen. The ovary walls become the
acorn, and the petals and sepals fuse into what becomes the "cap" on
the acorn.
Other cells at the tip of the branch
elongate and swell into a tiny
spray of yellow balls. These "catkins" have many tiny spheres, and each
opens and releases thousands of pollen grains. These are blown into the
air and some reach the pistils of potential acorns and pollinate them.
Pollen and female flowers appear on a tree at slightly different times
thus assuring cross-fertilization, and at the same time, other bud
cells divide and grow into the leaves.
The acorn is a hard, one-seeded, dry
fruit like a chestnut or hazelnut
and contains about 35% water, 10% fat, 4% protein, and 4% crude
fiber. It can vary in length from less than 1/2 inch to more than
2 inches and is made up of an embryo enclosed in seed leaves (properly
called cotyledons) and covered by a shell. When it germinates, it first
puts out a strong root that buries itself into the ground, and then
later an upright shoot.
Botanists divide oaks into two
groups—white oaks and red oaks (or
sometimes called black oaks). The trees in these two groups differ
chiefly in the shape of their leaves and in how long it takes their
acorns to mature.
Oaks vary widely in size and in the
way they grow. Some never become
taller than small shrubs while others reach heights of more than 100
feet. Many live for more than 200 years but grow slowly and usually do
not bear acorns until they are at least 20 years old.
Wisconsin white oaks have grayish bark
and leaves with seven or nine
rounded lobes. Their acorns form in the spring, mature during the
summer, and are shed in the autumn when they germinate almost
immediately. Good white acorn crops are irregular and occur only
every 4 to 10 years. Bur oaks are the largest of the whites and can
grow up to 80 feet tall with a leaf canopy diameter of up to 100 feet.
Their acorns are the largest of all the native acorns and can reach
1½ inches long. Each is almost round with a bur or moss-like
fringed cup covering half or more of the nut. It can send down a
taproot four feet deep just in the first year.
Wisconsin red oaks are divided into
three species—the northern red, the
black and the scarlet oak. All three usually have leaves with seven or
nine sharply pointed lobes and their acorns need two growing seasons to
mature. In forest stands, red oaks begin to bear fruit at about age 25
but usually do not produce seeds abundantly until about age 50 and then
at irregular intervals, usually every 2 to 5 years.
The acorns of the red oaks have a
relatively high content of tannin (a
bitter compound used to tan hides), compared to those of the white.
Native people used rock grinders to break open the red acorns, and they
would soak them in the streams for many days before using them. Most
animals prefer those of the white oaks, but eat the reds as well, as
poor nutrition absorption due to tannins may be overcome by the sheer
volume. So, deer, pigs, squirrels, quail, jays and many other wild
animals eat as many acorns as they can, although they sometimes leave
them for a few weeks on the ground to leach before they eat them. The
good news is that on these mast years, there are often more acorns than
the animals, birds, and insects can eat, leaving some to germinate and
assure that oaks will flourish for many years to come.
--------------------------------------------
October 24, 2010: What's So Different
About Woodpeckers?
Whoever first named the woodpecker
could not have given it a more
descriptive moniker. Only a few of the 180 species spend much time
doing anything else, and those live in areas where there are no big
trees. All woodpeckers have some characteristics in common: strong,
pointed beaks that act as chisels to remove bark to find hiding
insects; long sticky tongues, which possess bristles that allow them to
grab and extract insects deep within a hole; feet which have two clawed
toes pointing forward and two back to help them grasp a vertical
surface; and stiffened tail feathers, which they use as props so they
can peck away.
The largest of the seven woodpecker
species in our area is the
pileated, a term that comes from the Latin word for “capped”. It
is nearly crow-sized, and is mainly black with a red crest and a white
line down the sides of the throat. We often see one flying from tree to
tree in the woods, showing flashes of white from its underwings and
giving its typical ki-ki-ki-ki call. It is an important member of the
wildlife community as it is constantly ripping up old stubs and stumps
in its search for ants (its favorite food). In addition, it
excavates a new nest cavity each year and then abandons it for the use
of other birds and animals in succeeding years.
In contrast to the large pileated, the
downy woodpecker is the smallest
woodpecker in North America. It is mainly black on the upper parts and
wings, with a white back, throat and belly and white spotting on the
wings. Adult males also have a red patch on the back of the head, which
the female lacks. They feed mainly on insects, but also eat seeds and
berries, and in winter, downies are regular visitors at our
birdfeeders.
Strangely, the much larger hairy
woodpecker has virtually identical
plumage to the downy, although they are not closely related. The hairy
is medium-sized and is about 10 inches in length, while the downy is
only 6 ½ inches long. Both are permanent residents and forage on
trees, pecking off insects at the bark surface in summer and digging
deeper in winter.
Another medium sized woodpecker we
often see at our feeders in the
winter is the red-bellied. Its common name is somewhat misleading, as
the most prominent red is on the head. It is mainly light gray on the
face and underparts but has distinctive black and white barred patterns
on its back, wings and tail. The reddish tinge on the belly that gives
the bird its name is usually hard to see.
The redheaded woodpecker is a rather
close relative of the red-bellied,
but looks entirely different. It is strikingly tri-colored, with a
jet-black back and tail, white underparts, and a red head and neck.
Once abundant, populations have seriously declined presumably since the
arrival of European starlings that compete for nest sites in dead trees
in the woodlands.
The Northern flicker has two
characteristics that set it apart. It is
one of the few woodpecker species that often migrate at least a short
distance southward for the winter, and is the only one that commonly
feeds on the ground. We have the yellow-shafted variety in Wisconsin,
while a similar species—the red-shafted—lives farther west, the names
referring to certain feathers in their wings.
The only other woodpecker we see in
Wisconsin has elaborate plumage and
a fancy name—the yellow-bellied sapsucker. The male is predominately
black and white with yellow underneath and red forehead and throat,
while the female is similar but has a white throat. The sapsucker has
the clever habit of drilling holes in trees and then eating both the
sap and the insects that are attracted to it. It is also the only
woodpecker in eastern North America that is completely migratory,
sometimes going as far south as Panama.
Male woodpeckers almost always have
bright red on their heads that
flashes as they pound on a tree, sending both visual and auditory
signals to potential mates or rivals. This is primarily a spring
activity but may occur at any time, and the birds sometimes damage
buildings, road signs, and any other handy objects that might hide
edible prey or just act as sounding boards for their pecking. This can
be a problem if it is your house siding that is being attacked!
--------------------------------------------------
October 17, 2010: Flies
and More Flies
This is the time of the year when
householders often wonder where they
have gone wrong to have attracted or even propagated the flies that are
crawling on their windows, buzzing about their kitchen, and generally
making big nuisances of themselves. That is the bad news; the good news
is that the insects’ presence is not the result of anything anyone has
or has not done. These are probably cluster flies.
Cluster flies are common household
pests that resemble houseflies, but
have not come from poor garbage disposal, feces, rotting carrion or any
other putrid material. Their similarity to houseflies is only
superficial as they hold their wings parallel to the body instead of in
a triangular arrangement as do houseflies, they are covered with fine
golden hairs, and, most importantly, they lay their eggs on earthworms
instead of decaying material. The larvae consume the worms, pupate, and
in the fall, emerge and look for warm, sheltered spots in which to
spend the winter. This makes our homes attractive refuges for them and
the only way to prevent their entry is to seal every available crack.
Houseflies, on the other hand,
typically lay their eggs on animal feces
and garbage. They originated on the steppes of central Asia, but now
occur on all inhabited continents and are always found in association
with humans. White, legless maggots hatch from the eggs and grow
to about one-half inch before entering the pupal stage and forming a
dark brown cocoon. The adult houseflies emerge in as little as two days
under optimal conditions and can fly one or two miles in search of
suitable egg-laying sites. Houseflies spit out saliva onto solid food
to predigest it, and then suck it back in as they can only ingest
liquids. As many as ten to twelve generations may occur annually.
Stable flies are often confused with
houseflies but are larger and both
males and females feed on the blood of animals, including humans, often
biting around the ankles. The bites are painful but are not known to
transmit disease to humans. Females lay their eggs in rotting straw and
manure, moist piles of animal feed and yard waste.
Blowflies are often called bottle
flies because their shiny blue,
green, black or bronze color resembles colored bottle glass. Blowflies
are about the size of houseflies or slightly larger, and lay their eggs
inside the bodies of dead animals although they are also attracted to
garbage. The gases produced cause the carrion to have a bloated
appearance leading to the common name. Another similar fly is the flesh
fly that is dark-colored like the housefly but slightly larger. It also
usually seeks carrion or scraps of meat on which to lay its eggs.
Gardeners often have to combat another
fly when they bring fruits and
vegetables into their kitchens. The fruit fly is only about 1/8 inch
long and usually has red eyes. It lays its eggs on fermenting fruits or
other moist, organic materials, and upon emerging, the tiny larvae feed
on the soft surface. The reproductive potential of fruit flies is
enormous; given the opportunity, each female will lay about 500 eggs,
and the entire lifecycle from egg to adult can be completed in about a
week. Fruit flies are primarily nuisance pests but they do have the
potential to contaminate food with bacteria and other disease-producing
organisms.
There are some 120,000 different kinds
of flies. They, along with
gnats, maggots, midges, and mosquitoes are all close relatives and make
up one of the four largest groups of living organisms. There are more
known flies than vertebrates, and only the cold arctic and Antarctic
ice caps are free of them. The economic importance of the group is
immense as flies transmit an untold number of diseases and destroy
great quantities of food, especially grains and fruits.
Despite this negative picture, flies
are vital members of the wildlife
community. They are pollinators or regular visitors of more than 500
species of flowering plants and pollinators of over 100 cultivated
plants. In addition, they are near the bottom of the food chain and so
provide a major portion of the prey of many of our birds, insects, and
a number of other creatures. We couldn’t do without them,
nuisance that they may be.
---------------------------------------------------------
October 12, 2010: If Spiders
Could Fly....
This might seem to be a strange time
of the year for babies to arrive,
but in the spider phylum, it is quite commonplace. Furthermore, the
spiderlings are usually so small that they would go unnoticed except
for one characteristic—their mode of transportation. As soon as they
crawl out of the egg casing, they extrude threads of silk into the air
and let themselves be carried away by passing breezes. You have
undoubtedly seen these delicate strands as they glisten in the sunlight
and perhaps wondered at their source.
The spiderling raises its abdomen and
releases a thread that grows
longer and longer into the wind until there is sufficient upward lift
to carry it off. Although most rides are only of a few yards, they can
at times reach heights of up to 33,000 feet and be transported to every
spot on the world. Spiders are often one of the first inhabitants of a
devastated area like that after the eruption of Mt. Krakatoa in August
1883. Within six months scientists had already reported microscopic
spiders spinning their webs. Many sailors have reported that spiders
have been caught in their ship's sails, far from land.
Spider silk is a fiber composed of
complex protein molecules that the
creature uses mainly to make webs or other structures which catch prey,
or as nests or cocoons for protection for their offspring. Although
different species of spider and different types of silk have different
protein sequences, a general trend in spider silk structure is a
sequence of amino acids, some of which stack to form hard crystals,
while the rest remains as elastic less-organized material. These give
spider silk its extraordinary properties.
A spider's dragline is only about
one-tenth the diameter of a human
hair and is remarkably strong. Its tensile strength is comparable to
that of high-grade steel but with the advantage of being extremely
lightweight: a strand of spider silk long enough to circle the Earth
would weigh less than 18 ounces. It is also especially elastic, able to
stretch up to 140% of its length without breaking. Steel can be
stretched only 8% and nylon around 20%.
There are seven different known glands
located on a spider's abdomen
which produce silken thread and each produces a type for a special
purpose. Each spider possesses only some of these glands and not all
seven together. For example, one common California garden spider
produces five different types of silk: dragline silk is very strong and
tough and is used for the web's outer rim and spokes and the lifeline;
capture-spiral silk is sticky, extremely stretchy and tough and used to
trap prey; tubiliform silk is very stiff and used to create egg sacs;
aciniform silk is the toughest and is used to wrap freshly captured
prey; and minor-ampullate silk is used for temporary scaffolding during
web construction.
Humans have used spider silk
throughout history. Polynesian fishermen
used the thread of the golden orb web weaver as fishing line, while in
the New Hebrides, spider web was used to make net pouches for carrying
small objects. Some tribes in New-Guinea used webs as hats to protect
their heads from the rain.
During World War II, the threads of
some orb weavers were used as hairs
in measuring equipment and the threads of the black widow in telescopic
gun sights.
In 1709 a Frenchman, Bon de
Saint-Hilaire, demonstrated the possibility
of making fabric from spider silk. Many egg cocoons were boiled, washed
and dried and the thread was collected with fine combs and used to
produce socks and gloves. It was soon found that this would never be
profitable, however, as 1.3 million spider cocoons were needed to
produce one kilogram of silk.
There is commercial interest in
duplicating spider silk artificially,
but it has been very difficult to find a viable process. The most
promising involves cloning spider genes and inserting them into the DNA
of E. coli bacteria that would then replicate them. This seems to work
on a small scale but not in the quantities needed.
In the mean time, the spiders continue
to manufacture their amazing
silk to catch their food, house their young, and even to fly a
little...
------------------------------------------------
October 5. 2010: Bears: Who'd Have
Thought?
On several occasions we have
encountered black bears while visiting
northern Wisconsin and found it interesting, but it is a different
experience to have proof that one is wandering in our neighborhood.
While no one to my knowledge has actually seen the animal, its image
was captured by a wildlife cam last week just down the road. (A
wildlife cam is a flash camera that can be installed in the woods and
is triggered by any creature that passes by.) Now everyone is on alert,
wanting to catch a glimpse.
Fifteen years ago, bears were uncommon
in central Wisconsin and almost
never seen in the south, but that is not the case these days. Karl
Malcolm, wildlife ecologist, says that a healthy bear population up
north has forced bears to seek new territory. Following nature's
highways—rivers and wooded stretches—they have moved south and are now
spreading throughout Wisconsin's patchwork of forest and farm fields.
Black bears are an important and
impressive part of Wisconsin's
dwindling wild landscape. Adult male boars can grow up to 6 feet in
length, usually weigh 300-400 pounds, and measure 2 to 3 feet tall at
the shoulder. The smaller females, or sows, weigh up to 450 pounds and
measure 4 to 4.5 feet long. Infant cubs are born quite tiny but by the
time they are two months old, they weigh about 6 pounds.
The black bear is usually covered with
dense, coarse black fur although
brown and cinnamon color phases can occur. About 25 percent have white
markings of various shapes and sizes on their chests. They lumber about
on short, pigeon-toed legs giving a roly-poly appearance but they are
very strong, especially in their legs and shoulders. When they need to,
they can gallop over 30 miles per hour, climb trees, swim, and can
stand erect on their hind legs and walk for a few steps.
Black bears are omnivores; that means
they eat anything—fruit, berries,
nuts, grass, leaves, insects and insect larvae, fish, honey, trash, the
grease from grills, small mammals and carrion. As they have moved south
they have developed a taste for corn and especially sunflower seeds,
and therefore are attracted to birdfeeders.
A Walworth County property owner has
reported seeing a black bear north
of Delavan on Hazel Ridge Road in Sugar Creek Township. DNR Spokesman
Greg Matthews reports that this sighting is the 31st this year, with
most of the animals in Dane, Sauk, Iowa and Grant counties. An adult
male bear needs about 27 square miles of his own territory for mating,
while a female bear tends to stick within eight square miles of her den.
Any lone bear seen at this time of
year is most likely to be a young
male that is looking for new territory, but even a few females with
cubs have been observed. One such was reported near Leland this spring,
10 miles north of Mazomanie in Sauk County. “That tells us she was bred
down here,” Matthews said. “So we have at least one confirmed permanent
residence.”
Young boars were sighted this year in
Verona and Waunakee, a single
bear in the Town of Clyde in Iowa County, a young boar hit and killed
by a vehicle on Interstate 39 north of Portage in Columbia County, plus
several reports in Crawford and Columbia Counties. It is thought that
most of the bears leave the area after the breeding season, presumably
to return north, although female bears with young evidently remain in
the south throughout the summer.
Although a few bears are obviously
making themselves at home in our
area, the DNR states that there is no cause for alarm. While they are
wild, strong and unpredictable, humans have co-existed with bears in
northern Wisconsin for centuries and only a few common sense measures
are recommended. Don’t knowingly attract a bear to your yard by leaving
pet food or smelly garbage outside; they do come to bird feeders so you
might want to stop feeding during the summer, as well. Should you meet
one outdoors, wave your arms and make noise to try to drive the animal
off. Then slowly back away and give the bear an escape route.
Black bears are most active at
twilight though they sometimes are out
and about anytime, day or night. They are actually timid and generally
afraid of people, so consider yourself fortunate if you chance to see
one.
------------------------------------------------------------
September 28, 2010: Collies and Burs
Collies are our favorite dogs, and we
have had one or two in the family
for the last 50 years. Daisy joined the others early in the summer,
taking her place in our fond memories, and a few weeks without a dog
convinced us that we needed to fill the vacant hole she left, even in
our advanced age. Now Sunny has claimed our hearts and enlivened
our days, and we wonder how we could have thought we could get along
without her.
Sunny’s family gave her up to the
humane society in the spring as she
was too lively and vocal in their new urban home, and the
Minnesota-Wisconsin Collie Rescue group placed her with one of their
foster families until a home could be found. She was five years old and
seemed perfect for us and so she has proved to be. She has made it her
job to keep the deer, rabbits, woodchucks, and squirrels away from the
farmyard and chases them up into the wooded hillsides with great
enthusiasm. The only problem is that she also sweeps the area with her
long fur, collecting a variety of burs and sticky seeds.
Most of our plants have completed
their growth processes and have
either died or are going dormant, and Mother Nature has developed some
fascinating techniques for the spread of each species. If all of its
seeds fell to the ground under the parent plant, the result would
probably be overcrowded masses of a single species in a limited area,
but this is seldom the case.
Some plants provide their offspring
with sails or parachutes and then
hold them up in such a way that the wind can lift them into the air and
carry them some distance before dropping them to the ground. Some give
the seeds tasty appendages that entice insects or other creatures to
carry them off to their nests, while others surround the seeds with
edible fruits or berries that accomplish the same goal.
Equally ingenious is the trick of
encasing the seeds in coats that grab
hold of any passing creature, forcing it to carry them away. A
considerable number of plants cover their seeds in this manner armed
with an array of sharp curved hooks, such as those found on avens,
stickseeds, tick-trefoils, and burdock.
Yellow, or the very similar, woodland
avens are not well known species,
but if you spend any time in rough country you undoubtedly have picked
up some of their seeds. In the summer, they bear small yellow
five-petaled flowers that are then replaced by spiny green balls that
will adhere to anything that touches them. They can grow several feet
tall, making a patch of them a formidable barrier.
Tick-trefoil (often called
stick-tights or beggar's-ticks) has lovely
pink flowers arrayed on arching stems at a time when the woods are
often dark and lacking in much color. However, the plants later produce
slender legume fruits that break into small, one-seeded joints covered
with tiny barbed hairs. The individual joints are so flat that they are
exceedingly difficult to remove from your clothing when the barbed
hooks latch onto the threads in your socks, pants or sweater.
Virginia stickseed is another weed
that has become quite common in our
woodlands. It is a member of the borage family and has small white
flowers that hang in slender racemes during the summer. The flowers are
easy to miss but the numerous prickly fruits that hang downward from
its stems will come off with the slightest touch and stick so tightly
to fur or clothing that they are almost impossible to remove.
The most familiar is probably the
burdock, with its one-seeded dry
fruit enclosed in leaf cup covered with long hooked spines. One day in
1948, an amateur Swiss naturalist, George de Mestral, went on a nature
walk with his dog and returned covered with burs. He examined them
under his microscope and saw the numerous small hooks clinging to the
tiny loops in the fabric of his pants. The story has it that he
envisioned a unique, two-sided fastener, one side with stiff hooks like
the burs and the other side with soft loops like the fabric of his
pants and called it Velcro® a combination of the words velour and
crochet. And the rest—so the saying goes—is history.
---------------------------------------------------------
September 21, 2010: The Miracle of
Migration
There are definite hints of autumn in
the air, and walks around the
farm indicate that many of the birds have already left us for their
winter homes. Swallows, thrushes, warblers, and flycatchers are
tropical birds from Central and South America who visit us for only a
few short summer months.
It is believed that they and other
birds migrate because this behavior
expands the available nesting and food gathering areas of the world.
Tropical days are only 12 hours long but northern summers have extended
days that provide many extra hours for gathering food. It takes a great
amount of effort and time to feed three or four youngsters, that will
increase their hatching weight up to 50 times in just two weeks. When
nesting is completed and the weather is becoming cold and inhospitable,
however, these birds return to their true homes. Often at least a month
is spent in transit each way leaving only three or four months with us.
Some species begin to leave as soon as their young have become
independent, while others stay long into the autumn. Fall migration is
a protracted, often individual process propelled by shortening daylight
length, falling temperatures and north to northwest winds.
Birds have a number of unique
characteristics among the wild creatures.
Feathers provide the insulation necessary to maintain a high body
temperature, ranging from 107° to 113° F. Long wing feathers
act as airfoils that help generate the lift necessary for flight.
Well-developed pectoral muscles power the flapping motion of the wings
and a streamlined body shape and lightweight skeleton composed of
hollow bones reduce the amount of energy necessary to fly. They have
hearts which proportionately weigh 6 times more than those of a human
and can beat 1000 times a minute when in flight. The avian respiratory
system consists of two lungs plus special air sacs, and takes up 20% of
a bird's volume compared to 5% in a human.
In addition to these general
characteristics, migratory birds exhibit
specialized traits. Migrants generally have longer, more pointed wings
than non-migratory species, a feature that further minimizes air
resistance. Also, the pectoral muscles of migrants tend to be larger
and composed of fibers that are more richly supplied with nutrient- and
oxygen-carrying blood vessels. Migrants also possess internal annual
clocks which are set by day length and weather, and among other things,
these signal the bird to acquire and store an impressive quantity of
fat. A typical summer warbler weighs about 11 grams, but in the
autumn it may increase its body weight to 20 grams. In human terms,
this fuel strategy would be equivalent to a 150-pound person gaining 15
pounds of pure fat per day until tipping the scale at 300 pounds, and
then shedding 1.8 pounds per hour through vigorous exercise.
There are about 200 species of
migratory birds. The majority are
songbirds such as warblers, thrushes, tanagers, and vireos, but there
are also many shorebirds such as sandpipers, plovers, and terns, some
raptors such as hawks, eagles and vultures, as well as a number of
types of waterfowl. Migration distances vary greatly between species
and even between individual birds of the same type. The shortest
migrations are made by birds that breed in the southern United States
and winter in Mexico or the West Indies, a trip that can be as short as
a few hundred miles. These include some of the vireos, warblers,
buntings, northern parulas, and gray catbirds.
Some of the longest migrations are
made by shorebirds that nest in the
arctic tundra of northernmost Canada and winter as far south as Tierra
del Fuego (the southernmost part of South America), a one-way distance
of up to 10,000 miles. Other birds that winter in South America include
common nighthawks, Swainson’s hawks, red-eyed vireos, purple martins,
barn and cliff swallows, blackpoll, cerulean and Connecticut warblers,
scarlet tanagers, and bobolinks. A round-trip migration distance for
many of these species is as much as 13,600 miles. The absolute champion
is the arctic tern that travels 22,000 miles each year.
It is estimated that 90 percent of
songbirds hatched in any given year
fail to reach maturity and migration is a major killer. Untold numbers
of migrants die each year by striking plate glass windows, utility
lines and towers, and automobiles, in addition to the millions of birds
that fall prey to domestic cats. All these human-related challenges
come in addition to the natural risks of storms, water barriers, sudden
temperature drops, and natural predation.
We can help traveling birds by
providing a source of water (especially
moving as in a waterfall or fountain), leaving rough areas in the yard
that can provide shelter and food (insects and plants going to seed),
landscaping with evergreen and fruit bearing trees, shrubs, grasses and
vines, and maintaining nectar and other feeders until migration has
ended. We certainly treasure the species that spend the long winter
months with us, but anticipating the return of the migrants is one of
the great joys of springtime.
------------------------------------------------------
September 14, 2010: A Batty Story
It is always exciting to be part of a
wildlife study, and an
opportunity arose this week to help in a survey being conducted by a
section of the DNR concerning our bat population. Our farm had somehow
been identified as having two caves and it was hoped that they might be
serving as wintering hibernation sites for some the state’s bats. Most
bat species in North America feed on night-flying insects, many of
which are pests of forests, agriculture, and garden crops or pose risks
to human health and they play an extremely valuable role in our scheme
of things. The number of insects consumed annually by one million bats
is staggering--equivalent to 694 tons—indicating their extraordinary
importance—and they are now threatened.
Wisconsin has seven species of bats.
The largest and most widespread in
the Americas is the hoary bat, but even it seldom weighs more than one
ounce. The hoary bat, red bat and silver-haired bats live a solitary
life in the woods where their beautifully colored, silky fur blends in
with their surroundings. Each fall they fly south, reportedly to
the Gulf States, where they hibernate over winter perched in the
branches of trees. When warm weather returns, they fly north to spend
the summer in Wisconsin, often to the same tree each year to raise
their young.
Wisconsin’s four other bat species
remain for the winter but have to
find places where they can hibernate, as the insects upon which they
depend for food disappear with frost. They survive the long winter on a
few grams of stored fat, accomplishing this by dropping body
temperature and slowing metabolism. Two species, the northern myotis
and the eastern pipistrelles are common but relatively unknown. The
myotis hides in rock crevices, under bark or in hollow trees while
females with young prefer heavily forested areas. The
pipistrelles, our smallest bats, are sometimes mistaken for moths and
are rare near human structures, preferring instead to roost in dense
foliage. Both are thought to hibernate in caves in winter where they
are safe from freezing temperatures, but they have not been studied to
the extent of the big- and little-browns.
Big-brown and little-brown bats are
widely distributed throughout
Wisconsin and roost in colonies, often in accessible buildings that are
close to large insect populations such as barns. Our barn is the summer
home of a number of little-brown bats, tiny dark brown animals that
weigh less than ½ ounce and have wingspans of up to 11 inches. I
read that a little-brown bat may eat up to 900 small insects in an
hour, and average colonies may consume 500,000 insects or more each
night. The little-brown females form nursery colonies of dozens,
hundreds or even thousands of individuals while the males are thought
to spend the summer in scattered solitary roosts. They usually
hibernate in caves and mines, often clustered on cave walls or ceilings
curled up like furry balls.
They mate in the autumn, before
hibernation begins, and over winter the
male's sperm is stored inside the female's body. The infant is
conceived in spring and the female returns to the nursery colony, often
to the same place where she was born. There is usually one baby born
per female each year and it clings to a nipple constantly until it is
two weeks old. At that point, it becomes too large for its mother to
carry and will hang in the nursery while she forages. At three weeks it
learns to fly and by four weeks, it reaches adult size. Only about half
the babies survive to adulthood.
The big-brown bat is the one most
commonly seen in the summer, as it
often roosts in colonies in tree hollows, wall spaces, and buildings.
More tolerant of cold conditions than other species, it is the only one
that may over-winter in walls and attics. It is larger in size than the
little-brown, with an 11-13” wingspan and weighing 1/2 to 5/8 ounce.
While hibernating, the body temperature may be only slightly above
freezing, enabling these animals to survive in attics or more exposed
parts of caves or mines. This species has lived in our attic for some
35 years without any problem, and with all the benefits of their insect
control.
All of these hibernating bats (but
particularly the little-brown due to
its habit of forming large winter colonies) are feared to be at risk
due to the appearance of a strange new disease. White-nose syndrome has
already killed more than 1 million bats since first being detected in
New York in 2006, and the disease is now spreading westward. Its
distinguishing characteristic is a white fungus that grows on infected
bats' noses. Scientists do not understand how the fungus kills, but
they do know it infects the bats' skin and appears to interfere with
hibernation. During winter, healthy hibernating bats arouse briefly
about every two weeks, but infected bats wake up every few days,
perhaps because the fungus is itchy and irritating, and some scientists
believe this speeds the depletion of their energy stores and leads to
starvation. Some also believe that the bat’s immune system may detect
the fungus and respond by mounting a protective immune response,
burning precious calories in the process.
Members of the study team organized by
the Department of Natural
Resources visited us this past week, and we hiked up to the various
rock openings that had evidently been deemed to be “caves” in their
records, but we found no sites that they felt could over-winter bats.
They will be examining caves and mines throughout the area, hoping to
document the population while looking for any signs that the dread
disease has reached Wisconsin. We wish them well.
----------------------------------------------------------------
August 29, 2010: Sounds of a Late
Summer Evening
Warm August and September evenings are
filled with a chorus of strange
sounds, with insects such as cicadas (often mistakenly called locusts),
crickets and grasshoppers often predominating. Annual cicadas are
mostly large, blackish insects with greenish markings and large, clear
wings. They feed underground on tree roots for two to three years in
their nymph stage before emerging as singing adults, but due to
overlapping generations, we can hear some every year during late
summer. Their loud buzzing sound is made only by males, and is produced
by vibrating internal structures within their hollow drum-like abdomens.
Crickets sing at different tempos
depending on their species and the
temperature of their environment. Most species chirp more quickly the
warmer the temperature (approximately 62 chirps a minute at 13°C in
one common species). It is often possible to calculate the temperature
in Fahrenheit by adding 40 to the number of chirps produced in 14
seconds. Crickets, like all other insects, take on the temperature of
their surroundings, and as the temperature rises, their chemical
reactions such as those involved in the muscle contractions used to
produce chirping, occur more rapidly.
Only the male crickets chirp. A large
vein running along the bottom of
each wing has "teeth," much like a comb does. The chirping sound is
created by running the top of one wing along the teeth at the bottom of
the other wing. As he does this, the cricket holds its wings up and
spread, so that the wing membranes can act as acoustical radiators.
It takes a bit of imagination to hear
the “katydid..katydidn’t” song of
the long-horned grasshopper that has been given that name. It is
usually about two inches long and looks much like a green leaf with
legs. It makes its sound by rubbing a scraper, which is the sharp edge
of its front wing against a file found on the rough edge on the lower
wing, a process much like that of the cricket. The male starts to sing
from a chosen perch as darkness falls and the female’s “ears” that are
situated on her forelegs direct her toward to the loudest singing male.
An interesting research item is that the female can recognize her male
counterpart only when they are at the same temperature.
We are not the only listeners to the
insect chorus, as another
interested party lingers at the edge of the woods. The Eastern screech
owl is a small, nocturnal, woodland bird. It is only about 9 inches
long and weighs about 7 oz., but it is a formidable hunter, out from
dusk to dawn, but most active during the first four hours of darkness.
When prey is spotted, the owl dives quickly and seizes it in its
talons. Small prey will usually be swallowed whole on the spot, while
larger objects are carried in the bill to a perch and then torn into
pieces.
The male screech owl has a
lower-pitched voice than the female. His
most common call is a mellow, muted trill—each call lasting 2 to 3
seconds and consisting of about 35 notes, repeated at various
intervals. A second more recognizable call is a descending whinny,
often given during courtship, although we have been hearing it in the
farmyard the past few nights. A mated pair will sometimes sing a duet
consisting of both songs and also have been heard to bark or hoot at
other times.
This little owl flies fairly rapidly
with a steady wingbeat, rarely
gliding or hovering, but may flutter with erratic movements when
maneuvering through wooded areas. Its wings are broad and the head is
held tucked in giving the bird a stubby appearance when flying. It is
an opportunistic hunter and will attack any suitably-sized prey
although the most favored are small rodents and deer mice. It will also
hunt rats, chipmunks, squirrels, shrews, bats, and moles as well as any
birds it can catch, and will gobble up large flying insects and
anything else it considers edible.
Step out of doors after sunset and
listen to the sounds of the evening.
Another world awakens as darkness falls, and musicians tune up their
instruments for our wonder and pleasure.
-----------------------------------------------------
August 24, 2010: All That Glitters is
not Gold
The grassland outside my study window
has taken on an almost uniform
yellow color, as have most of the fallow fields in the area. Even the
most disinterested person usually knows goldenrod when he or she
encounters it—perhaps even more than the ubiquitous Queen Anne’s lace.
About 100 perennial species make up the goldenrod family, most being
found in the meadows and pastures, along roads, ditches and waste areas
across North America.
The botanical name of this remarkable
plant, Solidago, means “to make
whole” and it has been used as a healing herb since ancient times. For
Native Americans, it was a staple medicine, as nearly every tribe had
at least one variety close at hand. Called “sun medicine,” it was used
to treat everything from wounds and fevers to rheumatism and toothache.
It was also used as a charm, smoked like tobacco, woven into baskets,
burned as incense, and made into a dye.
Learning that goldenrod sap contained
natural latex, Thomas Edison
decided to see if he could use it as a source of rubber. He produced a
resilient, long-lasting product that Henry Ford made into a set of
tires for his own personal automobile. From the common weed that grew
to an average height of 3-4 feet and contained 5% yield of latex,
Edison produced a hybrid that grew to 12 feet and yielded 12% latex.
His research was turned over to the U.S. government when he died in
1931, but the project was dropped and never revived, even when rubber
became almost impossible to obtain during World War II.
Probably due to its prominent, golden
yellow flower heads in late
summer, the goldenrod is often unfairly blamed for causing hay fever in
humans. The fact is that the pollen causing these allergy problems is
mainly produced by the ragweed that blooms at the same time as the
goldenrod, but is wind-pollinated. Goldenrod pollen is too heavy and
sticky to be blown far from the flowers, and is thus mainly pollinated
by insects. To get the pollen in your nasal passages, you’d have to
sniff a flower close to your nose. Frequent handling of goldenrod and
other flowers, however, can sometimes cause allergic reactions.
A common sight among any cluster of
goldenrod stems is the presence of
round or elliptical swellings called galls. These can be caused by
fungi and viruses, but most commonly by insects; for example, when
certain flies and moths lay eggs on a plant stem or leaf, their larvae
hatch and tunnel into its tissue where they feed on the plant's cells.
The plant reacts by producing a tumor-like growth that houses and feeds
the grub.
There are three different insects that
use goldenrod in this fashion:
the apple gall fly, the elliptical gall moth, and the rosette gall
midge. This last one--a miniscule fly--lays its egg in a leaf bud and
the presence of the grub somehow keeps the stem from growing and
elongating, resulting in a thick tuft of leaves usually at the top of
the main stalk. The other two insects cause ball-like galls to form on
the plant stem that remain through the winter.
Although goldenrods are easily
recognized by their showy arrays of
hundreds of bright yellow flowerets, the various species are often
difficult to distinguish. Canadian goldenrod is our most common and
weedy type. There is some experimental evidence that this species
inhibits the growth of other plants by exuding chemicals through its
roots, although reportedly these results were obtained in the
laboratory and have not been proven in the field. The main problem it
causes is that its root system is made up of creeping rhizomes that
cause the plants to cluster, forming dense colonies that may crowd out
other plants.
It is virtually impossible to
eliminate this species from an area, but
removing seedheads and treating with an herbicide, not just once but
repeatedly as new plants appear, will hopefully create a situation
where diverse competition will hold it in check. Perhaps this is for
the best as some authors say that goldenrod is one of the most valuable
plants on the continent to feed our pollinators. Its high protein
pollen and tremendous nectar yields give many species of bees and wasps
their last good feed of the season.
----------------------------------------------------
August 17, 2010: Swallow Tales
Swallows and martins are members of a family of songbirds that are
known for feeding on the wing. They snatch up flying insects, selecting
the larger ones (regrettably, mosquitoes are somewhat down on their
preference list), and avoiding stinging insects such as bees and wasps.
Their flight may be fast and involve a rapid succession of turns and
banks when actively chasing fast moving prey, or slower and more
leisurely as they fly in circles, alternating flapping with gliding to
catch less agile victims.
We have six species in Wisconsin and they can be separated into two
groups—those that nest in cavities and houses, and those who construct
nests of mud that they plaster beneath overhangs, either natural or
manmade. The Northern rough-winged and bank swallows are fairly common
plain brown birds with light underparts and forked tails that nest in
cavities near the water, usually in burrows that may be up to two feet
in length. These birds forage in flight over water or fields, flying
low to scoop up flying insects, and both migrate to the Gulf coast and
south to Central America in winter. The Northern rough-winged swallow
derives its name from the outer wing feathers, which have small hooks
or points on their leading edges.
The tree swallow will nest in a natural or artificial cavity near water
but will also readily use a nest box, including one built for
bluebirds. We had a pair some years ago in a birdhouse near the
farmyard, only to have house sparrows chase them off, never to return.
The adult tree swallow has iridescent blue-green upperparts, white
underparts, and a very slightly forked tail while the female is more
greenish and less colorful.
The largest of the family is the purple martin, with an average length
of 8 inches from bill to tail. Adult males are entirely black with
glossy steel blue sheen, and a slightly forked tail while females and
young are less showy. (Within the family, the name "martin" tends to be
used for the squarer-tailed species, and the name "swallow" for the
more fork-tailed species.)
Purple martins catch a variety of insects from the air but fly
relatively high, so mosquitoes do not form a large part of their diet
despite many claims to the contrary. They make their nests in cavities,
and in many places they are almost entirely dependent on man-made
housing. The birds suffered a severe population crash following the
release and spread of European starlings during the last century, as
the more aggressive starlings and house sparrows took over many of the
martins’ nesting sites and killed their young.
Cliff swallows often breed in large colonies. They once placed their
conical mud nests beneath cliffs, but now usually build them under
overhangs of man-made structures such as barns, bridges, and the like.
The gourd-shaped nest is a covered bowl made of mud pellets, with a
small entrance tunnel on one side. A neighbor’s barn down the road is
host to dozens of these birds, and they often greet us with great
swoops and acrobatics as we pass. These are also the famous swallows
whose return every year to the Mission San Juan Capistrano from
Argentina is celebrated with a festival, although in recent years, the
swallows have been nesting in the Chino Hills to the north.
Probably the most frequently observed member of the family is the barn
swallow, a bird that often reminds me of a butterfly with its lovely
colors and long tails. I was amused to note that the first three
internet sites listed after a Google search were concerned with getting
rid of these birds despite their desirable qualities, as they are so
comfortable with building their nests near humans that they invade
porches, patios, and any available similar area. Not only do they
plaster their mud nests onto the building siding, dropping bits on the
floor below, but their chicks deposit their droppings there as well—a
mess not often welcomed by their human neighbors.
The adult male barn swallow is about seven inches in length including
its tail. It has steel blue upperparts and a rufous forehead, chin and
throat that are separated from the off-white underparts by a broad dark
blue breast band. The outer tail feathers are elongated, forming the
distinctive deeply forked "swallow tail", and there is a line of white
spots across its outer end. The female and juveniles are less colorful
and have shorter tail feathers. It is a fact that males with longer
tail feathers are generally longer-lived and more disease resistant,
and are more attractive to females.
One characteristic of the barn swallow that we find particularly
intriguing is that it seems to “play”. We have watched one carry a leaf
high into the air, let it go, and then snatch it as it flutters down
before carrying it aloft again. After a bit, another bird will swoop in
and grab it to join in the game. Once several were playing with a leaf
on the shed roof, allowing it to slide down the slope before flying
down to capture it. Wouldn’t it be fun to know what goes on in their
minds at such times?
-----------------------------------------------------
August 3, 2010: Bob..White!....
We have had a new family in the area
the past few weeks. Where they
came from is a bit of a mystery, as I’ve asked around among our closest
neighbors and no others have even seen them, let alone had any hand in
introducing them. In past years we have heard the distinctive whistle
perhaps two or three times —“bob-White! bob-White!”, but the birds
seemed to leave as quickly as they arrived and we saw no more of them.
We understand that these birds are notoriously difficult to see,
keeping hidden in tall grass or standing crops, and reluctant to fly,
preferring to sneak away instead. Even when flushed, they keep low and
soon drop back into cover.
This time, however, it was a family—at
least 14 mostly grown chicks and
2 adults. I saw them first parading down the road in a line (and so was
able to get a good count), and later several times around the farmyard.
Then one morning I was surprised to see half a dozen perched on the
railing of our north deck, while the others explored the garden below.
Since then they have again visited the porch, perhaps to get an
elevated view of the premises, and we wonder at their tame behavior.
The Virginia quail is a native “game
bird”— a designation given to
those species that are hunted for sport or food, including pheasants,
quail, grouse, and several other less well known types. It is more
commonly called northern bobwhite or bobwhite quail because of its
characteristic call, and its brown, speckled body weighs only 5-6
ounces. The male is distinguished by having a white chin and upper
throat and a white stripe running from the bill to the back of its
black head while the female is a little larger in size, and has tan
collar, eye strips and undersides.
Quail are bred and kept as poultry in
some parts of the world both for
eggs and meat. The common quail of Europe was previously much favored
in French cooking, but quail for the table is now more likely to be
domesticated Japanese quail. These are commonly eaten complete with the
bones, since these are easily chewed and the small size of the bird
makes it inconvenient to remove them. The eggs of quail are considered
a delicacy, and are sometimes used raw in sushi.
Northern bobwhites can be found
throughout the eastern United States
west to the Great Plains, usually in hayfields, pastures, prairies, and
oak savannah. They forage in nearby row crops and small grains such as
millet, wheat, milo sorghum, and other grains; however, quail are also
fond of weeds such as ragweed, partridge peas, and various vetches.
Grasshoppers serve as the primary diet of young bobwhites and are eaten
by adults as well. Shrubs, brush piles, and hedgerows are used
for hiding and roosting and this woody cover is vital for winter
survival.
Quail travel in coveys (groups) of
five to 30 birds during the
non-breeding season, but in March and April, pairs begin to form. Nests
are established on the ground hidden in dense underbrush, but usually
within 20 yards of openings such as fields or roads. A female quail
will lay one egg a day until twelve to sixteen eggs have accumulated
and then will brood them for about 23 days. If the first clutch of eggs
is unsuccessful, a breeding pair (perhaps the same pair or the female
may accept a different mate) will attempt to produce another clutch.
When the eggs hatch, chicks are up and running almost immediately and
will leave the nest within 24 hours, although they often stay with the
adults through fall and winter.
Northern bobwhites were abundant
historically in southern and central
Wisconsin, but intensive market hunting in the late 1800s and
subsequent changes in agricultural practices have resulted in dramatic
declines. They are now concentrated in the southwestern part of the
state, with only scattered populations elsewhere. Whistling bobwhite
quail route surveys have been conducted since the summer of 1949, and
the number of calling males per stop has decreased steadily, with a
spectacular drop in 2007 to 2009 of 74%. Winters temperatures were
below average with above average precipitation for those winters with
record rainfalls at the peak of hatching. A more significant long-term
factor is thought to be the changes in land use with continued losses
of grasslands.
The effort to save the species has
taken two forms: bobwhites are being
propagated in captivity in large numbers for release on hunting
preserves and natural areas, and considerable work is being been done
to restore the weedy, protective, and food-rich "edges" that the quail
prefer. In the first half of the 20th century, smaller farmers had
gardens and crops divided by overgrown hedgerows and fencerows that
provided close cover for birds. Large-scale agriculture cleared much of
the land, but now Conservation Reserve Programs (CRP) and
state-designed programs are putting large areas back into suitable
habitat. Also, Quail Forever has over 100 chapters in 25 states that
are working hard to encourage quail habitat projects such as tree
thinning and burning.
We hope that at least a few of the
family will survive to nest next
spring, and that quail will take up residence in our valley. We will be
listening for the bobwhite call come spring.
___________________________
July 27, 2010: The Not-so-Lowly
Milkweed
I used to think that milkweed was
little more than a nuisance weed,
sprouting where I did not want it, displaying blah-colored flowers, and
generally being of little use except as food for the monarch
caterpillar. I have since revised my opinion, as I have found
that even the common variety has a heavenly smell and its flowers are
complex and unique. At one time or another I have found specimens of at
least seven species here on the farm, each of them displaying the
characteristic flower made up of 5-parted cups crowned by five
swept-back petals. These are always arranged in clusters,
sometimes held erect, other times drooping on long stems.
All of the milkweeds, as every kid
soon learns, have a sticky white sap
in their stems and leaves. This sap has been used to treat various
ailments through the centuries; in fact, the plant’s Latin name,
Asclepias, was taken from Aesculapius, the legendary Greek god of
medicine. The treatment success rate of these doctorings is pretty
vague but the practices of applying the sap directly on a wart and as a
natural remedy for poison ivy are still common.
Milkweeds may cause mild dermatitis in
some who come in contact with
it, and analysis has shown that they contain alkaloids, latex, and
several other complex compounds including cardenolides, a type of
steroid, some of which are toxic and may seriously affect the heart.
The latex contains about 1 to 2% natural rubber, and unsuccessful
experiments were conducted by both Germany and the United States during
World War II in an attempt to use it as a substitute for tropical
rubber. After the War, these efforts were abandoned until Standard Oil
of Ohio became involved with milkweed in the late 1970s predicting that
billions of barrels of synthetic crude oil could be recovered from the
biomass of milkweed. Milkweed was grown like hay—it was cut, dried,
baled, and a crude oil substitute extracted—but they found that the
price was too high and the yield was too low.
Finally, in 1987, the Natural Fibers
Corporation was organized with two
goals—to grow milkweed, not as a source of crude oil, but to process
its pods to recover salable floss as a fill for jackets and bedding.
The milkweed filaments from the pods are coated with wax, and have even
been thought to be superior to down feathers for insulation. During
World War II, over 11 million pounds of milkweed floss were collected
in the United States as a substitute for kapok in life preservers
(kapok was the fluffy, yellowish fiber used for stuffing at that time
that was harvested from the seedpods of a tropical tree) and the boys
and girls from Wisconsin schools alone collected 283,000 bags of
milkweed fluff. This effort has led to a commercial product called
Hypodown that is used in comforters and pillows in the bedding
industry. This is a combination of white goose down and milkweed that
is touted to trap and suppresses the dust and dander that plague people
with allergies.
Pollination in milkweeds is
accomplished in an unusual manner, as the
pollen develops in "pollen sacs" that grow in pairs and are situated in
the slits of each flower. When an insect visits the flower, its feet or
mouthparts often slip into one of the slits and make contact with these
sticky objects. The sacs with the pollen inside are then carried to the
next plant and trapped in its slits allowing cross-pollination to take
place. The flower cluster then develops into a number of elongated pods
holding overlapping rows of seeds tucked inside. Each seed is equipped
with white silky filament-like hairs and is carried off by the wind as
the pods dry and split open.
Reportedly, most animals and insects
avoid eating milkweeds because of
their bitter taste, but some beetles, moths, and true bugs (besides the
highly publicized monarch butterfly) have adapted to feed on the plants
despite their chemical defenses, and even seem to gain protection from
predators in this way. Interestingly, all of these seem to be brightly
colored with orange and black, and some authorities suggest that the
colors are signals warning of their bad taste. It is also true that
some other plants actually benefit from their proximity to a milkweed
as it repels some pests such as wireworms. These are the larvae of a
variety of click beetle species, many of which attack a variety of
plants and are serious agricultural pests.
Regardless of its commercial value, we
enjoy half a dozen species of
milkweed on the farm. There is the bright orange butterfly weed, the
showy purple milkweed, the poke milkweed with its drooping clusters of
whitish flowers when few other things are blooming, the several green
types that seem to appear and disappear for no reason, and the whorled
milkweed, a delicate plant with radiating linear leaves and small
clusters of white flowers up the stem. Other types grow elsewhere in
various habitats, most notably the swamp milkweed that has lovely
purple blossoms. The next time you see one of these beauties, take time
to appreciate its blossoms and its aroma, and examine any insects
feeding there. You may be surprised at you what you find.
-------------------------------------------------
July 20, 2010: Nests and More Nests
Even the most unobservant walker has
at some time discovered a bird’s
nest, although it is often long after the family it nurtured was grown
up and flown. Birds use nests to protect their eggs and nestlings from
predators and weather extremes, and to help keep eggs and nestlings
warm. We usually think of them as supported by tree branches, but some
birds build nests on the ground, some in bushes, while still others
attach their nests to the sides of cliffs. Barn swallows are most often
seen around barns, porches and other outbuildings, while chimney
swifts, as the name implies, favor chimneys and other man-made
enclosures. Wrens will nest in almost any cavity, from an empty
watering can to a coat pocket (as well as David’s jeans).
Nest building is thought to be
primarily instinctive as the structure
and materials of nests are very similar across a species, even when
birds are raised in isolation from others of their kind. Still, some
learning is also involved because older birds usually build 'better'
nests than younger birds (especially those in their first breeding
season). Birds can make hundreds of trips to collect materials, and
while most seem to prefer grass and twigs, some use almost anything
that they can carry—even candy wrappers, cellophane, shredded money and
barbed wire. Which of the pair actually does the building varies by
species, and in some cases, both collect materials and join in the
construction. One of the more peculiar routines is that of the male
marsh wren, which builds as many as 10 dummy nests in his territory
before the female arrives. She then makes her choice and finishes it
with a lining of soft materials.
Researchers from Ohio Wesleyan
University suggest that some birds may
select nesting material with antimicrobial agents that protect their
young from harmful bacteria. "If the fresh herbs and plant materials
that parent birds bring into the nest have a sufficient concentration
of antimicrobial compounds, they could protect the nestlings from
harmful bacteria," says researcher Jann Ichida. Ichida and colleagues
tested 12 different volatile plant materials against feather-degrading
bacteria and results showed that several types of plant materials and
extracts did in fact inhibit the growth of a number of harmful
bacteria.
Not only are the method of
construction and materials used important to
nesting success but some birds consider orientation as well. In one
study, it was found that horned larks consistently situated their nests
adjacent to and north of objects such as a tuft of grass or a rock,
thus shading them in the hottest part of the day and providing
increased daytime ventilation of the prevailing winds. In addition, the
shade may also help conceal the nest from predators.
To hold a nest together and secured in
place, birds need good adhesives
and use a variety of natural substances to do the job, including mud,
saliva, spider webs, caterpillar silk, leaf mold, and certain plant
fibers. Materials that make up the nest can be intertwined, and
sometimes are actually woven together using grass, strips of leaves,
and twigs.
Bird nests vary from a simple
accumulation of materials on the ground
to elaborate refuges in or on secluded and elevated locations. It is
interesting to note that nest construction and placement often
correlates with the ability to fly. Scrape nests that are just simple
depressions in the ground or in the leaf litter are used by turkeys,
grouse, chickens, quails, and pheasants—all relatively weak fliers.
Doves, cuckoos, herons and egrets use a bit more effort and build
simple ground nests or crude elevated nests.
More efficient fliers usually
construct nests in a bush or tree or on a
cliff or rock ledge, and young raised in elevated and cavity nests have
strong wings and chest development along with smaller legs. Some of the
most complex nests are associated with swallows, orioles and weaver
finches. The latter two groups often live in areas where there are many
predators and build their intricately woven pendant nests hung from the
thin branches of bushes and trees. Perhaps the most predator-proof
nests are those of swallows and swifts that often construct mud
structures attached to the most remote overhanging feature within their
territory.
Most birds construct a new nest for
each brood, and there is good
reason. There are at least 2500 species of blood-feeding mites and
ticks from 40 families that are closely associated with birds, and
virtually no species is free of one or another. Adults and nymph stages
of these blood feeders live in the nests or on the birds themselves,
and usually multiply rapidly, sometimes building up huge populations
that can cause considerable damage by slowing development or even
killing chicks. With this in mind, it might be wise of David to
consider retiring those old jeans that are currently holding the wren
nursery and get a new pair.
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July 13, 2010: Horns on Worms?
The sun had just set and the sky was a
palette of pastel pinks,
yellows, and purples—a sight worth savoring—and I walked out onto the
deck. I disturbed the hummingbird that was getting its sugar fix for
the night, but then another flyer took wing almost under my feet. I
ducked as it came within inches of my head but then laughed at my
reaction for it was just a moth, albeit the largest one I had seen this
year. It fluttered off before I could make identification, but its size
led me to guess that it might have been a tomato hornworm or, more
properly, a five-spotted hawk moth.
This is a large, heavy-bodied moth
with narrow front wings, a mottled
gray-brown color with yellow spots on the sides of the abdomen and a
wing spread of 4 to 5 inches. Its larvae feed only on tomato plants or
their relatives such as garden peppers, potatoes and eggplant, and
weeds such as horse nettle, jimsonweed and nightshade. Eggs are
deposited singly on the leaves in late spring and hatch six to eight
days later. The larva is white but as it grows it sheds its skin
several times, and eventually becomes pale green with white, lateral
"V-shaped" markings and a black projection or "horn" on its tail that
gives the caterpillar the name "hornworm."
Hawk moths are somewhat different from
the giant silk moths that I have
enjoyed tending in past years. The silk moths look and act more like
butterflies with their wide outstretched brightly-colored wings. Then
too, their larvae encase themselves into silken cocoons before
splitting their skins a final time and transforming into pupae. When
these hatch, the adult silk moths live only long enough to mate and lay
eggs and then die as they have only rudimentary mouthparts and eat
nothing during their short lives. The males have wide feathery
antennae, while those of the females are somewhat narrower and less
showy.
The hawk moth, on the other hand
usually has narrow forewings that are
patterned to look like tree bark, leaving any color to be displayed on
the hind wings or body where it is mostly hidden when at rest. It flies
more like a hummingbird, with rapid beating of its wings, and has the
ability to hover, a capability that has evolved only three times in
nectar feeders: in hummingbirds, certain bats, and these moths. Its
antennae are generally not very feathery, even in the males, but its
body, legs, and wings are densely covered in narrow scales that look
much like hairs. It feeds as an adult through a long tube proboscis
that it keeps curled tightly until needed and then extends to probe
deeply into flowers to reach any nectar. The larvae do not spin cocoons
but simply burrow into soft dirt and there transform into pupae,
protected only by their hard brown “skin”.
Besides the tomato hornworm (that is
often not a welcome resident in
our gardens), we have several other hawk moths in our area. The catalpa
sphinx moth is brown in color with a wingspan of about 3 ½
inches. Its larvae feed exclusively on catalpa trees and when they
mature, one can find a number of the yellow caterpillars with the wide
velvety black stripe down their backs on the ground searching for a
soft spot into which to burrow.
More common is the white-lined sphinx
moth, a more colorful insect
whose wings are marked with (guess what?) white lines, and who will
visit your petunias, phlox and other fragrant evening flowers. Take a
flashlight and walk through your garden at dusk and you very well may
see the reflections of your light in the eyes of one or more of these
lovely moths. Their larvae feed on any of the varieties of portulaca,
and if your yard is anything like mine, you will have plenty of this
around that you may know as pigweed or purslane. This is a trailing
annual weed with small yellow flowers and reddish, fleshy stems and
leaves whose joints will form roots when they come in contact with the
ground.
If my moth was a tomato hornworm, I
will have to watch my tomatoes
carefully in the coming weeks to see if they have been targeted as food
for its offspring. Soon, any resulting caterpillars will reach their
mature size of 3 to 4 inches, at which point they will drop from their
plants and burrow into the soil to pupate. Adult moths will emerge in
about 2 weeks and will mate and deposit the eggs for another
generation. These caterpillars will form pupae by early fall that will
remain in the soil all winter and emerge as moths next spring.
We find these caterpillars are easy to
control if their numbers get too
large, as their presence is obvious from the areas of devoured leaves
and they can be simply picked off. There are also natural factors that
help to control them. The egg stage and hatching larvae are often eaten
by various predatory insects such as lady beetles and green lacewings,
while the growing caterpillars are targets of a small braconid wasp.
This insect lays its eggs directly on the caterpillar and when the eggs
hatch, its larvae burrow in and feed on the inside. These mature,
emerge, and spin cocoons that appear as white projections protruding
from the hornworm’s body, and eventually kill it.
I grow plenty of tomatoes, however, so
that I can share some of the
plants with the few caterpillars that are likely to make it to
maturity. Having these beautiful moths flying around our home on summer
evenings is one of the pleasures made possible by having a big garden
in Wisconsin.
--------------------------------------------------------
July 6, 2010: Butterflies
Until the rain brought an end to our
lovely stretch of fine weather, it
has been difficult to walk from the porch to the road without
scattering dozens of butterflies. Painted ladies, red admirals,
red-spotted purples, and a few other species flitted about, mostly on
and above the gravel driveway. The first two species are insects that
cannot tolerate our winter conditions and either are killed or migrate
to warmer areas each fall. Then in the spring the butterflies must move
up into the state again, and often do so in large numbers. The
red-spotted purple is hardier and the last brood of the summer goes
into hibernation as larvae, pupating and emerging as adults the
following spring.
Perhaps it was the warmth of the sun
but there also was probably
moisture beneath the stones that drew them. Butterflies seem to detect
the same basic flavors as we do, sweet, sour, salty and bitter, but
have different perceptions as to what they find desirable. Manure,
urine, decaying plant wastes, and other damp debris will bring them by
the dozen, presumably to obtain certain minerals and salts that their
bodies require.
It is easy to assume butterflies are
attracted to our gardens by seeing
the bright colored flowers; however, what more likely brought them was
the perfumed invitation that the flowers were sending out. Butterflies
have very sophisticated senses of smell and taste as these are their
main windows on the world, rather than the sight and sound that we and
most other animals use. Many of the receptors are on their antennae,
the two "feelers" that all insects have on their heads and which give
them an enormous amount of information about their surroundings.
Antennae are usually segmented tubes,
moved by tiny inner muscles.
These may be covered with minute hairs, knobs, bristles, or scales that
are extremely sensitive to odors and chemicals, movements, and physical
contact. The main functions are usually smell and taste, however, and
butterflies often wave their antennae about as they "sniff" the air for
telltale scents and odors. Insects need two antennae, incidentally, to
establish direction. Tiny as they are, they can distinguish which
is receiving the stronger scent and therefore can fly toward the source.
Insects use smell to communicate,
orientate, navigate, detect humidity,
find food and water, locate suitable egg-laying sites, and identify
friends and foes. The olfactory receptors are porous pegs or cones
covered by a very thin layer of cuticle, and containing sensory nerve
cells. They can detect scent molecules in the most minute quantities
and are usually concentrated on the antennae, although there may be
some on the mouthparts as well. Butterflies and moths can be drawn to
mates over distances of a mile or two by the pheromones produced by one
or the other.
Butterflies rely on taste as well as
smell to determine whether liquids
are suitable to drink. Taste receptors are similar in structure and
function to the olfactory receptors as both detect the presence of
various chemicals, airborne in smell, and by contact in taste. Taste
receptors in insects are usually found on and around the mouthparts but
butterflies have them on their antennae and on their feet as well.
Thus, a butterfly is led to a food source by the smell, lands upon to
it taste with its feet and then probes with its feeding tube for
confirmation. A monarch butterfly's sensors have been shown to detect a
sugar solution of only 0.0003 percent strength and are more than 2000
times more sensitive than those on the average human tongue. Observers
have also determined that the taste receptors in the feet trigger an
increase in the butterfly's internal blood pressure that causes the
tube-shaped tongue to uncoil automatically.
In addition to the antennae,
butterflies have bristles and hairs
growing on their bodies and legs. Each one grows from a socket and has
a ball joint at its base that can move freely in all directions.
The socket is supplied with a network of microscopic nerve fibers that
detect and transmit any movement to the brain. Insects also are
supplied with fluid-filled chambers that are lined with tiny bristles
and contain solid granules called statoliths. As the insect moves
about, the statolith tends to remain stationary in the chamber and the
bristles on its wall detect its position, relaying information about
the insect's orientation and balance.
We have a great variety of butterflies
and moths that live in our yards
and wild areas, some with wingspans of less than an inch or so. Despite
all the fascinating complexity of their bodies, the beauty of their
wings, and their value as pollinators, butterflies are considered to be
just another delicious if somewhat elusive meal for the birds that
inhabit our farmyard.
----------------------------------------------------------------
June 26, 2010: An Accessible
Volcano Caldera
Walking around on the floor of a
volcano crater is an experience. Jets
of boiling hot water spurt into the air from holes in the earth’s crust
and gases and steam rise from fumaroles on every side. Visitors must
keep to the boardwalks that allow them to reach many of the more scenic
spots, and they are warned not to stray off the paths or risk breaking
through the thin crust that separates them from the heat below.
Yellowstone Park lies on top of an
area where hot, molten rock rises
towards the surface, and over the past 17 million years or so, volcanic
eruptions have caused the overlying land to collapse forming a
geographic depression called a caldera that is some 45 by 30 miles. The
largest violent eruption excavated the West Thumb of Lake Yellowstone
around 150,000 years ago, and the most recent lava flow occurred about
70,000 years ago. Currently, volcanic activity is visible in the form
of 10,000 geothermal vents scattered throughout the region, including
the famous Old Faithful Geyser. The Yellowstone caldera still
experiences between 1000 and 2000 measurable earthquakes a year, though
most have a magnitude of 3 or weaker. The most recent swarm, as a close
grouping of quakes is called, started after the January 2010 Haiti
earthquake and was the second largest ever recorded in the Yellowstone
caldera.
Geologists closely monitor the
Yellowstone plateau, which rises and
falls about half an inch yearly: however, from mid-summer 2004 through
mid-summer 2008, the land surface within the caldera moved upwards
significantly, with 8 inches of rise at the White Lake GPS station.
Fortunately, by the end of 2009, the uplift had slowed and appears to
have stopped, so that the U.S. Geological Survey and the Yellowstone
Volcano Observatory now state that they "see no evidence that another
such cataclysmic eruption will occur at Yellowstone in the foreseeable
future although such events are not really predictable."
Our country has done a number of
things right through the years, and
one of them was the establishment of the national park system.
Yellowstone is one of the gems of this group and contains some 3470
square miles of forests, grasslands and water (an area larger than
Rhode Island and Delaware combined), with altitudes from about 5300 to
11,400 feet. In addition to the geothermal vents, there are
approximately 290 waterfalls, 15 ft. or higher and flowing year-round,
the tallest being the lower falls of the Yellowstone River at 308 ft.
The park also contains one of the world's largest petrified forests. It
boasts 67 species of mammals, including 7 species of native hoofed
animals and 2 species of bears, 322 recorded species of birds (148
nesting species), 16 species of fish, 6 species of reptiles, 4 species
of amphibians. It harbors 2 threatened species, the Canada lynx and the
grizzly bear, and one endangered species, the gray wolf.
The animal we saw most frequently in
the park was the bison. It can be
up to 6 feet tall, 10 feet long, and weigh up to a ton. The heads and
shoulders are massive, and both sexes have short, curved horns, which
they use in fighting for status and for defense. We felt it also has a
sense of humor as we twice watched a huge animal leading its buddies in
a leisurely stroll along the center of the park road blocking all
traffic. We could imagine him saying to his cohorts, “Let’s go have
some fun with those dummies in the automobiles.” I’m sure the people in
the back of the mile-long lines of stalled vehicles could only guess
what was causing the problem.
It was surprising to see how slow was
the recovery from the 1988 fires
that affected a third of the park. Five fires apparently burned into
the park that year from adjacent public lands, but the largest, the
North Fork Fire, started from a discarded cigarette and burned more
than 410,000 acres. Many of the canyons and hillsides are still covered
with standing snags as well as criss-crossed fallen trunks and
branches, and the regenerating trees among them are only about ten to
fifteen feet high, even after 22 years. It will be many years before
the park will reach its pre-fire appearance.
Driving across the country past fields
of corn, then vast areas that
are good only to pasture cattle and finally lands where only occasional
antelopes seem to be able to eke out a living, gives us a new
appreciation for the courage and fortitude of our ancestors who
followed that route less than 200 years ago. Each stream and hill must
have presented a challenge, to say nothing of the larger rivers and
finally tall mountains that lay in their paths.
One of the moving moments of our trip
west occurred at the Garden of
the Gods, a public park donated to the city of Colorado Springs in 1909
by the estate of Charles Elliott Perkins. We rounded a corner among the
huge rock outcroppings and came upon a large group of teenagers sitting
together on the hillside. It was a high school choir from Florida on a
trip to Colorado and they were singing “Oh beautiful for spacious
skies...” a song written by Katharine Bates in 1895. She had traveled
by train from Massachusetts and was inspired by the World's Columbian
Exposition in Chicago, the "White City" with its promise of the future
contained within its alabaster buildings, the wheat fields of Kansas,
and the view of the Great Plains from Pikes Peak. We, too, felt the awe
she expressed in her poem as we traveled much same route. We live in a
beautiful country.
----------------------------------------
June
15, 2010: Strange Lights in the
Meadow
Mother nature has done it again – put
together another seemingly
impossible scenario that our scientists with all their expertise and
ingenious paraphernalia have not been able to duplicate – and it has to
do with a little bug that almost all of us as children collected on a
summer’s evening. A firefly is about ½ inch long, cigar-shaped,
and flies about in our yards, but what makes it exceptional is the
light it gives off, as even its eggs and larvae glow. There are about
136 different species around the world and they are common in the
eastern half of this country as well as in warm, humid areas around the
world.
Usually at dusk, the male firefly
emerges from hiding and flies about,
emitting one or a series of short flashes depending upon his species,
at regular intervals. The female waits on a low perch, and when a male
approaches, will give off an answering flash. Exchanges of signals are
repeated several times until the pair find each other and mate. Then
with luck the male will escape, as given the chance female will devour
him. After mating, the female will deposit her eggs in damp soil,
and in about three weeks young sowbug-like larvae will hatch with tiny
spots on their undersides that glow softly. All firefly larvae produce
light, possibly as a defensive measure, as it has been shown in the
laboratory that predators avoid such glowing objects after experiencing
their taste. The larvae are voracious predators that eat earthworms,
snails, slugs, and mites, injecting strong digestive juices into their
prey before sucking out the insides and leaving an empty skin. Most
firefly larvae live one to two years and are found in rotting wood or
other forest litter. In late spring they change into pupae, and in
about 10 days, emerge as new adult beetles that will live as long as it
takes to mate and produce eggs, often only a few days.
The last few segments of an adult
firefly’s abdomen are made up of
thousands of specialized cells that contain luceriferin and luciferase,
rare chemicals that generate light in the presence of oxygen, together
with an enzyme that provides energy for the process. The light emitted
by fireflies is unique in that nearly 100 percent of the energy is
given off as light. This is in contrast to tungsten electric lights
where only 10 percent of the energy is emitted as light and the other
90 percent is given off as heat. Although a few other insects can
produce light, fireflies are the only ones that can flash their lights
at will and it has only been recently that scientists have discovered
how it is accomplished.
Neurobiologists at Tufts University
were puzzled because they could
find no nerve link to the light-producing cells in the firefly’s tail,
although they did find that they could cause the cells to glow if they
exposed them to molecules of nitric oxide gas in the presence of
oxygen. Furthermore, they observed that the cells had a thick outer
layer of mitochondria, a substance that reacts with oxygen to create
energy for the cell and guessed that these mitochondria might be
blocking any light-creating chemical reaction. They also discovered
that a signal from the insect’s nervous system activated an enzyme that
produced nitric oxide that deactivated the mitochondria producing the
light. As the nitric oxide signal decayed, the mitochondria resumed
their oxygen consumption that turned the light off -- all of this
occurring in a fraction of a second. The fact that nitric oxide passes
through cell membranes, degrades within seconds and must be made fresh
for each use makes it an important transmitter and signaling molecule.
The really fascinating part of this
story is that scientists have found
that luciferin and luciferase are extremely useful as markers in
research on such problems as cancer, multiple sclerosis, cystic
fibrosis and heart disease. As all living cells already contain the
energy-providing enzyme, injection of the firefly's chemicals cause
flashes of light that can be measured and used to detect energy
problems in human cells. Now, electronic detectors, using firefly
chemicals, are used to signal that milk, food or water may be
contaminated with bacteria, and detectors have even been placed in
spacecrafts to look for earth-life forms in outer space. I read that if
as little as one quadrillionth of a gram of the enzyme enters the
rocket's detector, a flash of cold light will be given off and recorded
by earth-bound scientists.
Although most of the luminescent
species are insects, the capability is
also present in some bacteria, fungi, algae, one-celled animals,
segmented worms, arthropods and fishes. Some, like the fireflies, use
their light in courtship, while others use the flashes to frighten off
enemies or attract prey. The colors produced vary, as well, as some are
red, others blue-green or yellow. The problem is that not only are
luciferin and luciferase rare but they have proved difficult to
synthesize. This has made the propagation of fireflies a high priority
activity in some circles and the Sigma Chemical Co. of St. Louis,
Missouri purchases and provides fireflies throughout the world for
conducting research in a wide variety of scientific areas. I am told
that they will pay a penny for each bug if you will send them at least
25,000. Our bugs are completely safe from me, anyway...
June 8, 2010: One Bear, Two Bears,
Three Bears, More???
Bears are very much in the news these
days and I thought we might do
well to learn a bit more about them. North America has three or four
bear species, depending upon whether you count the grizzly and Alaskan
brown bear as variations on a theme or different species. The brown
bears live on Alaska's coastal range and nearby islands. Standing
erect, some males (boars) tower over eight feet, and on four feet,
stand as high as four and one-half feet at the shoulder. Most big males
weigh between 800 and 1,200 pounds with females averaging between 500
and 800 pounds. Grizzlies are somewhat smaller, standing three and
one-half feet at the shoulder and weighing up to 800 pounds. Once
widespread throughout much of western North America, grizzlies can now
mostly be found from inland Alaska across northern Canada to the Hudson
Bay, although a few remain in Montana and Yellowstone Park.
The polar bear is a huge, long-necked,
pear-shaped animal with thick,
whitish-yellow fur. Despite rumors to the contrary, a 2002 U.S.
Geological Survey of wildlife in the Arctic Refuge Coastal Plain noted
that the polar bear populations “may now be near historic highs” with
some 20,000 to 25,000 bears. Adult boars stand four feet at the
shoulder and are about eight feet in length and weigh about 1,000
pounds while females are typically smaller and lighter.
The black bear is the smallest of the
North American bears and is
thought to have arrived from Asia on the Bering Land Bridge about
500,000 years ago. Unlike the formidable grizzly, the shy black bear
has learned to adapt to man, and inhabits forests, swamps and mountains
from Alaska to the Gulf Coast. Though known to attack when provoked,
the black generally gives humans a wide berth.
Black bears mate in June and early
July and will breed with several
mates. During the 7 1/2 month gestation period, the fertilized eggs
float free in the sow’s uterus until late November when the egg
implants into the uterine wall and begins to develop. (This phenomenon
is called delayed implantation.) The cubs are born while their mother
is still in her winter sleep and are only 6 to 8 inches long, weighing
7 to 12 ounces. They develop rapidly and are able to leave the den in
late March with the female. The sow is a very attentive, protective
teacher, feeding her cubs and protecting them from other adult bears,
especially boars that would kill the cubs. Since it takes cubs 2 years
to become independent, sows do not breed every year and don’t chase her
cubs away when she again becomes pregnant. They will reach full size in
4 to 6 years.
Black bears locate their food by
relying on their keen sense of smell.
They feed mostly at twilight and through the night, and then spend the
daylight hours loafing in dense cover. They have large canine teeth,
but their molars are flattened for grinding and chewing tough plant
food rather than slicing through flesh, and plants make up a large
portion of their diet. They will eat just about anything, however:
fruits, berries, green leaves, tubers, acorns, nuts, ants, beetles,
bees, insect larvae, honey, fish, mice, squirrels, eggs, dead animals,
greasy grills, and garbage.
If food is scarce, bears will wander
and will be seen more frequently
during daylight hours. When they first emerge from their dens in
mid-March they are very hungry and because plants are still dormant at
this time of year, they must rely on small mammals and carrion for
food. As plants begin to sprout, bears switch to mostly green leaves.
With their powerful forelimbs and strong claws, they also rip open
rotten logs and anthills to feed on the insects, eggs, and larvae
hiding inside. They particularly enjoy tearing open beehives in trees
to feast on the stored honey.
In early summer the bears gorge on
wild strawberries and juneberries,
then on raspberries, gooseberries, blackberries, blueberries and
elderberries as each ripens, sometimes eating leaves, stems and all.
Later they switch to apples, wild grapes, acorns, and nuts – items that
that are high in fat and will help them put on the weight they need for
their long winter's sleep. Sometimes bears attack domestic livestock,
particularly lambs, piglets and calves. They will also raid beehives,
orchards, cornfields, and backyard birdfeeders, and can cause damage
when they rummage through garbage cans or demolish greasy grills left
out overnight. Healthy black bears can live 20 or 25 years, and hunting
is the primary method used to control their population from becoming
too large for society to tolerate.
Although some black bears can become a
nuisance, they are a very
important and beneficial part of Wisconsin's wild community. With
proper management, they will continue to provide thrilling subjects for
observation, photography and study. Report bear sightings to DNR
wildlife biologist Becky Roth, Spring Green, at 608-588-3432 or email
at Rebecca.roth@wisconsin.gov.
-------------------------------------
May 25, 2010: Robins, Brown
Thrashers, etc.
After months of waiting for spring,
suddenly it almost seems like
summer. The wooded hillsides are varying shades of green again, the
lawn grass needs to be mowed every few days, iris are blooming in
profusion, and not only do the male robins awaken us each morning with
their songs, but their first chicks are out of the nest and pleading
for food with never ending chirpings.
The American robin is a member of the
thrush family, all medium-sized
birds with rounded heads, longish pointed wings, and usually melodious
songs. It is named after the European robin because of the male's
bright orange-red breast, though the two species are not otherwise
similar. The female tends to be duller than the male, and the juvenile
is paler yet and has dark spots on its breast. During the breeding
season, male robins grow black feathers on their heads to attract
females but once the mating season is over, these feathers are lost.
While robins occasionally over winter
in the northern part of the
United States, most migrate south, departing in September and October
and returning north in February and March. The robin begins to breed
shortly after returning to its summer range and is one of the first
North American bird species to lay eggs. The nest is built by the
female and is commonly located in a dense bush or in a tree fork,
although she is very adaptable and will build in all sorts of
locations. She collects long coarse grass, twigs, paper, and feathers
held together with mud and moulds the nest into a cup shape with her
body and feet. She often then adds a final lining of soft grass, before
laying 3 or 4 “robin’s-egg-blue” eggs. It takes about 2 weeks to
incubate the eggs and the young stay in the nest for about 15
days. The female will begin a second clutch almost immediately
after they fledge, while the male continues to feed the first
youngsters another week or so.
The robin’s diet is mostly made of up
fruit and berries supplemented by
insects, larvae and worms. The reason we see so many robins searching
the lawns for worms is that these are the main food of the chicks in
the nest. At times, the robin will cock its head to the side toward the
ground and it was previously assumed to be listening for a worm. Now it
is understood that the bird is really watching for any tiny movement,
as its sight is much more acute than its hearing. When it does find a
worm, it often has to tug hard to pull it out of its hole. This is
because a worm's body has hair-like bristles called setae that help the
worm crawl and also to grip and anchor it firmly in the ground.
While many of our bird species are
declining, the robin is doing very
well and is thought to number about 320 million individuals. At one
point, the bird was even killed for its meat, but it is now protected
by the Migratory Bird Act. Its only problem is that it is a known
carrier for West Nile Virus. While crows & jays are often the first
noticed deaths in an area, the robin may be more responsible for the
transmission of the virus to humans. This is because while crows &
jays die quickly the robin survives longer, spreading it to more
mosquitoes that then transmit the virus to humans and other species.
The robin is not the only bird we are
watching these days, as a pair of
brown thrashers is also busy in the back yard. These birds are
robin-sized but are bright reddish-brown above with thin, dark streaks
on their buffy underparts and have long rufous tails. They like to feed
on the ground, poking long curved bills into the grass and ground
debris to find insects, seeds, and almost anything else edible they can
find. We assume the nest is in one of the thick shrubs back of the pond
but have been reluctant to look for it as the thrasher is notorious for
attacking any intruders and is quite capable of drawing blood with that
sharp beak.
The brown thrasher’s most interesting
characteristic is its song, as
researchers have been able to document some 3000 distinct phrases—many
of them mimicking the songs of other species or other sounds. The male
sings a series of short repeated melodious segments from an open perch,
each one repeated once. These repetitions also set the thrasher’s song
apart from those of its close relatives, the Northern mockingbird or
gray catbird, as mockingbirds repeat in groups of 3 or more while
catbirds do not repeat themselves at all.
The main enemy of both the robin and
brown thrasher is the housecat, as
the birds often nest in urban communities where the cats abound. In
rural areas, owls, hawks, crows, jays, snakes, squirrels, chipmunks and
raccoons also attack them, although most of these enemies feed on the
young or eggs, not the adult birds. Only 25% of the young survive the
first year and the average lifespan is only about 2 years. Populations
of brown thrashers are declining slowly across their range, perhaps
because of loss of habitat in the East and the elimination of fencerows
and shelterbelts across the Plains states.
We spend many contented moments
sitting on our porch watching the
various species of birds come to drink and bathe in our little pond.
Several types of finches, warblers, hummingbirds, flycatchers, jays,
bluebirds, red-wings, grackles, woodpeckers, tanagers, grosbeaks, and
mourning doves (and I’ve undoubtedly missed some), visit us regularly
and entertain us with their antics. We have great birding right at our
doorstep!
------------------------------------------
May 18, 2010: When is a Mouse not a
Mouse?
It must be tough being a mouse. Almost
every animal and bird in the
area wants to eat you, and should you find a warm and seemingly safe
house in which to live, the human resident sets a trap and tries to do
you in. Furthermore, there are a number of other related species vying
for all the available territories and food.
There are two general groups of
so-called mice in Wisconsin. One is
made up of jumping mice – mouse-like rodents that are distinguished by
their enlarged hind limbs, cheek pouches, and very long tails that are
used for balance while bounding. In Wisconsin these rodents can
sometimes be found in forest, pasture, cultivated fields or swamps.
They are nocturnal and generally live alone, and when disturbed, they
leap off with enormous bounds of eight or ten feet in length. The
female places her nest in clefts of rocks, under downed timber or in
hollow trees, and there are generally three litters in a season.
Members of the second group are called
murids and include true mice,
rats, and voles. These typically have slender three to four-inch bodies
plus scaly tails, and pointed snouts with prominent whiskers. Murids
generally have excellent senses of hearing and smell. The various
species may live almost anywhere and eat a wide range of foods with the
aid of powerful jaw muscles and gnawing incisors that grow throughout
life. Murids breed frequently, often producing large litters several
times per year. They typically give birth between 20 and 40 days after
mating, although this varies greatly between species. The young are
born blind, hairless, and helpless.
The house mouse is one of the most
numerous murid species and was
originally native to Asia—perhaps India. It spread to the Mediterranean
area about 8000 BC, across the rest of Europe by 1000 BC, and has since
been carried to all parts of the globe. It has been domesticated as a
pet and has been bred as a laboratory animal where it has proved to be
an important tool in biology and medicine.
The typical house mouse is 3 inches
long with another 3 inches of tail.
It is usually brown or gray and has short hair and a naked tail and
ears. House mice thrive in and around homes and commercial structures
as well as in open fields and agricultural lands. They consume and
contaminate food meant for humans, pets, livestock, or other animals
and often cause considerable damage to structures and property. They
also can transmit pathogens that cause diseases such as salmonellosis,
a form of food poisoning.
We are much more sympathetic with the
white-footed mouse, a native
species. It is about the same size as the house mouse but has white
underparts. This mouse can climb trees and uses its tail as a prop and
to help balance as it climbs. It is usually found in brushy fields and
woodlots and eats seeds, nuts, berries, fungi, and insects. It is adept
at food-hoarding and stores nuts and seeds during the winter months
when other food sources are scarce.
The deer mouse is very similar to the
white-footed but has a longer
multicolored tail. It also is a climber and likes to nest high in a
tree while the white-footed tends to stay closer to the ground. The
female deer mouse can breed at all times of the year, and so has the
highest reproduction rate among the murids. Deer mice feed on seeds,
fruits, spiders, leaves, and some fungi, and during the winter months,
invertebrate creatures compose about one-fifth of the deer mouse's
diet.
A third mouse, the Western harvest
mouse, is larger and can be found
from the Great Lakes to the Pacific Coast in grasslands, prairies,
meadows, and marshes. These mice average more than 5 inches in length
plus a 3-4 inch tail, and have