A Northwoods Almanac
for Aril 15-28, 2016 by John Bates
Cold Feet
Watching
ducks and geese standing on lake ice makes my feet feel very cold. A friend
recently said that the feet of ducks and geese don’t freeze in the winter because
no blood circulates through them. But that’s not the case.
The blood
moving through the naked portions of a bird’s leg would lose enormous amounts
of heat in the winter, which has forced birds to compensate by employing a countercurrent heat exchange mechanism. It works like this: the
main artery that carries warm blood down the leg is positioned next to a large
vein that brings cooler blood back from the foot to the heart. A shunt near the
base of the toes allows most of the arterial blood to pass directly into the
vein and return without going through the toes and webs, and thus losing even
more heat.
The
blood returning to the heart absorbs heat from the warmer arterial blood next
to it. So, heat is exchanged all the way from the bottom to the top of the leg
with the blood arriving back in the body only slightly cooler than what
originally left to go to the legs.
To get blood into the feet, some of
the blood at the bottom of the leg bypasses the shunt and runs through a
capillary network into the toes, which is just enough to keep the blood a few
degrees above freezing. It makes for cold feet, but not frozen feet.
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| hooded mergansers - photo by Bev Engstrom |
Become a
Landlord
Now is the time to become a
bird landlord and “rent out” homes to new tenants. Some 85 species nest in tree
cavities in North America, of which about three dozen will nest in birdhouses.
In our area, the most common tenants will be black-capped chickadees, eastern
bluebirds, house wrens, purple martins, wood ducks, common and hooded
mergansers, kestrels, and most of our woodpeckers.
Birds won’t rent your houses unless
you fulfill their needs. The size of the entrance hole limits which species can
enter – and which pest species such as starlings cannot – and the floor plan
must accommodate the species' nest. For example, to attract chickadees, which
typically nest in dense stands of small trees, put up birdhouses that have 1
1⁄4-inch diameter holes, centered 6 inches above the bottom of the nesting
floors, in small tree thickets.
Bird renters would like a home
security system on their digs, and you can offer this by putting a stovepipe baffle
below the house to keep out raccoons, house cats and other predators that steal
eggs and chicks. One writer says, “If you put a birdhouse up on a pole without
a guard, you are basically serving lunch.”
Remember, too, that
dying and fallen trees make excellent
homes for cavity nesters. One unusual example is the brown creeper which
nests between strips of loose bark and the trunk of a tree.
Prairie Chicken Dancing
I
haven’t visited a prairie chicken lek for many years now, but I still vividly remember
the experience. Sarah Krembs reminded me of this when she sent me some photos
and a description of her recent visit to a lek near Wisconsin Rapids. She
wrote, “We had to be in the blinds at 5:30 and wait for the chickens to show
up. First one, and then about a dozen more all at once.
“The
sound is most unusual . . . like a mourning dove crossed with a morning
barnyard hen. Only one female was there yet, so it was mostly the males who
were defending their territory and fighting with each other . . . When they
puff their neck sacks out and drum their feet, it is sure a sight to see. Sometimes
when the males were puffed up they also did a kind of walk in the funniest way.
It was like they were sliding in a straight line . . . as if they were gliding
across the ground on ball bearings. It was such a “non-natural” motion that it
truly fascinated me.”
If
you’re interested in reserving a blind to watch these remarkable birds, go to: www.uwsp.edu/wildlife/pchicken/Pages/viewing.aspx
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| prairie chicken dancing - photo by Sarah Krembs |
The Big Thaw
Five
species of frogs in northern latitudes freeze during the winter: wood frog,
chorus frog, spring peeper, gray tree frog, and Cope’s gray tree frog. In the
next few weeks, they’ll all thaw out, and the first to begin singing will be
the wood frog, followed almost immediately by spring peepers.
Wood
frogs and peepers hibernate by hiding under the leaf litter on the forest
floor. By hibernating on land, the frogs can become active as soon as the snow
melts and breed in temporary ponds formed by meltwater.
But frogs
can't dig underground like toads do. Their water-permeable skin is no barrier
to ice, and so they freeze. Their eyes even turn white because the lenses
freeze. Their blood stops flowing and as much as 65% of the frog's total body
water is converted to ice. Breathing, heart beat, and muscle movements all
stop, and the frog lives in a virtual state of suspended animation until it
thaws.
They
survive largely by building up high concentrations of sugars to keep the
insides of their cells from freezing. Ice forms all around their internal
organs, but not in the cells.
So,
when you hear the first wood frog or spring peeper in the next few weeks,
consider that they have been frozen for nearly six months. The pandemonium of their
calling makes all the more sense in that light.
Spring Break for Black Bears
Black bears should all be emerging from hibernation now. While some will
undoubtedly smash a few bird feeders this spring, according to data from the
National Center for Health Statistics, only about 36 human deaths from
black bears occurred across North America in the 20th century. For every person killed by a black
bear in North America in the same period, 60 were killed by domestic dogs, 180
by bees, 350 by lightning, and 90,000 were murdered. So, while always being
wary and cautious, enjoy their awakening!
Salmonella
Time
With the arrival of spring
snow melt, this is the time of year when salmonella bacteria can affect birds
at your feeders. The smaller songbirds, such as pine siskins, redpolls and
goldfinches that weigh only a half ounce, are most at risk.
Salmonella presents itself via
a bird at your feeder that appears constantly “fluffed up” and is lethargic and
easily approached. While the bird may appear “fat,” it’s really starving and
trying to stay warm, even on a warm day with food. Please take the time to
clean your feeders with soapy water and then with a solution of one part bleach
to nine parts water.
Birds can also become sick
from leftover seeds and hulls that begin to ferment. Rake up excess seed or hulls
from under the feeder, bag them, and put them in the trash.
Lead
Poisoning
Mary Madsen in Presque Isle sent me a photo of a bald
eagle that she captured in March on Twin
Island Lake and took to the Raptor Education Group in Antigo. The eagle was
suffering from lead poisoning. Mary noted, “Sadly, it did die. It was a
l7-year-old eagle, banded in the U.P.”
Lead has no business being used for hunting and
fishing. The Raptor Education Group’s website in Antigo says this: “Lead
poisoning this time of the year usually comes from a bird eating from a
discarded animal that was shot with lead ammunition and was either placed in the
woods for predators to eat or died in the woods of its injury. Often those that
want to feed animals with carcasses have no idea that they contain lead, or how
lethal it is. Lead the size of a grain of sand causes lead poisoning in a human
child. We hope all hunters make the switch to copper jacketed bullets when
hunting. It is safer for wildlife, not to mention their own family.”
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| eagle with lead poisoning - photo by Mary Madsen |
Sightings:
First-of-the-year (FOY)
Mid-March: Patrick Kessenich sent an
excellent photo of a bobcat seen in his yard on Clear Lake in Manitowish
Waters.
 |
| bobcat - photo by Lori Kessenich |
3/27:
Sarah Krembs sent excellent photos of a red crossbill that stunned itself by
smacking into one of her windows.
 |
| red crossbill - photo by Sarah Krembs |
3/29: Mary
and I spotted our FOY turkey vultures in Minocqua, and a FOY northern harrier
in Manitowish.
3/30:
FOY song sparrows, fox sparrows, purple finches, and phoebes all in Manitowish.
3/31 - Carne Andrews observed 6
males and 1 female wood ducks foraging in the grass on the bank of the
Manitowish River.
4/3 – Carne also spotted a FOY male
yellow-bellied sapsucker.
4/6: FOY: Sue DeFrancisco observed a hooded merganser
hen entering her wood duck box.
4/7: Pat Schmidt reported the FOY common loon for our area on Silver Lake
west of Hazelhurst. Silver Lake, just 40 acres in size, is one of Walter
Piper’s study lakes (see www.loonproject.org), and has had a
breeding pair of loons for many years.
4/8:
With our eight inches of snow this day, the birds were frantic around our
feeders. A woodcock appeared under the feeder late in the day and spent many
minutes probing through the snow for food. It was there the next day as well. Given
that invertebrates constitute 80% of a woodcock’s diet, and they only
occasionally eat seeds, I think this woodcock was very hungry.
 |
| woodcock probing for food through 8 inches of new snow - photo by John Bates through a window |
4/10:
John Randolph reported a FOY osprey on a telephone pole nest near McNaughton.
Ice-out
According to 40 years of ice-out
data collected by Woody Hagge, the average ice-out date for Foster Lake, a
relatively deep, 39-acre seepage lake in Hazelhurst, is April 17. I expect this
average date to hold true for many lakes in our area.
Celestial Events
Look on 4/17 for Jupiter about two
degrees above the waxing gibbous moon.
The “Grass Appearing,” “Awakening,” “Maple Sugar,”
full moon occurs on 4/22. Unfortunately, the peak Lyrid meteor shower also
occurs this night and will be washed out by the brilliance of the moon. This
will be the most distant and thus smallest full moon of the year, some 14%
smaller and 30% dimmer than the closest full moon for this year, which will
occur on November 14.
We’re up to 14 hours of
daylight as of 4/23!
Look in the pre-dawn on 4/25 for
Saturn and Mars to be just below the
waning gibbous moon.
Please share your outdoor sightings and thoughts: call me at
715-476-2828, drop me an e-mail at manitowish@centurytel.net,
or snail-mail me at 4245N Hwy. 47, Mercer, WI.
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