Hunger and mating keep mammals from hibernating around here

It's the dead of winter. Do you know where your wildlife is?

As the snow flies and the wind howls, many of us retreat into TiVo'ed hibernation. But look out the window for a minute at the snowy outdoor world. Picture what it looked like last summer. Where are all the animals that flourished in your yard and garden last August? The robin who nested in your hedge last spring? How 'bout that skunk family who terrorized the neighborhood in May? The fireflies who danced in the dark last July? The butterflies who graced your garden? The mosquitoes who chased you indoors? Where are they now?

There are as many different strategies for getting through the winter as there are different kinds of animals. The ways that animals overwinter are pretty cool - er, warm, I suppose - and we might learn a few things from them while we huddle in our heated homes.

Let's start with hibernation and the popular assumption that all mammals hibernate the winter away. Hibernation is a state of depressed metabolism in which heart rate, respiration and temperature drop dramatically. Hibernators' sleep is so sound that (like my teenager) they are impossible to wake up.

But hibernation is the exception and not the rule among our mammals. The only true hibernators in our area are woodchucks, thirteen-lined ground squirrels, and bats. None of the other mammals in Illinois hibernate. Even black bears, erstwhile residents of Illinois, are not true hibernators.

Raccoons, opossums, squirrels, and their mammalian kin, on the other hand, are dormant during cold snaps. Dormancy involves sleep - usually in a nice, secure shelter - but is not characterized by the drastic drop in metabolism and respiration as in hibernation.

Thus you may see a raccoon during a reprieve in the winter storms, or the tracks of an opossum in the snow. You may smell a skunk who's been out and about.

"The animals den up in the coldest parts of winter," explains Mark Romano, wildlife control specialist, "especially if there's significant snowfall. Some find their way into attics, window wells and under porches."

If there's a warm spell, out they come, looking for food.

"You may not even know they're there all winter," Romano says, "but toward late January they become noticeable, even if it's cold and there's snow on the ground. They're driven by more than food. Their hormones are driving them to reproduce."

And once love-struck, they can create quite a ruckus on a cold winter night.

How about those controversial carnivores, the coyotes and foxes?

"Coyotes are hardy animals and much of the time they go about their business irrespective of weather," says Bill Graser, wildlife biologist for the forest preserve district. "But when it is exceptionally cold and windy coyotes often seek areas with good thermal cover. We often find them hunkered down in dense cover such as a cattail marsh when it was really cold out."

Foxes, too, will den up in severe weather but come out to scrounge up calories in the form of mice and voles.

Migration is another overwintering strategy. Migration is driven by food sources, however, more than weather. A nectar-eating bird such as the ruby-throated hummingbird who visits your flowers in the summer would face famine in our winter landscape. In order to ensure a source of food, it makes a marathon journey south to warmer climes. Weighing in at about 0.11 ounces, this little powerhouse can wing it all the way to Central America, sometimes a distance of 1,000 miles from its summer home - and this includes a nonstop flight over the Gulf of Mexico.

Consider another bird, that most-welcome harbinger of spring, the robin. We've been taught since kindergarten that robins "go south" for the winter and return in spring. Well, yes and no. Robins do move for the winter. But Kane County is south for some.

Different populations move different distances southward for the winter. We may see some robins here in January who came from their nesting grounds in northern Minnesota. Similarly, robins who nested here last summer may be down by the Gulf of Mexico today. Thus there are robins here in winter, subsisting on berries and other fruit.

Some species of bats migrate southward. The silver-haired bat and the red bat migrate south, and then go into hibernation in their winter quarters. We are likely to find big brown bats here in the winter, though. They have a propensity to hang out in attics year-round. Although you can't blame them for finding good real estate in a tough market, their presence in a house is a cause of consternation and concern.

From birds to bats, we come to butterflies. Most butterflies and moths overwinter as eggs. There are a few notable exceptions. Perhaps the most notable is our state insect, the monarch butterfly, who not only overwinters as an adult but overwinters some 3,000 miles away. It is not adapted to survive the cold winters here, so it makes a remarkable journey each year to wintering grounds in central Mexico. Mourning cloak butterflies also overwinter as adults, but they stay put. Mourning cloaks literally hang out under loose bark or in crevices and cracks in wood and debris.

Butterfly expert Doug Taron explained in Chicago Wilderness magazine that mourning cloaks survive the cold in "a state of suspended animation." They produce "natural antifreezes - such as sorbitol," says Taron, to avoid freezing in the brutal cold snaps of winter. Because they are already adults with developed wings, mourning cloaks are among the first butterflies you'll see in early spring - sometimes when there's still snow on the ground.

Remember those brown furry-looking caterpillars you see crawling on the sidewalk in the fall - the ones that curl into a ball when you pick them up? These are "woolly bear" caterpillars and they find their way under logs and porches to curl up for the winter. They overwinter in the caterpillar stage. There may be a few under your deck right now, snoozing the winter away. Come spring, they will resume where they left off in their life cycle and metamorphose to cocoons and from cocoons to moths. Isabella tiger moths, to be precise.

What about the fireflies that blinked like tiny strobe lights in the fields of midsummer? How do they make it through the winter? If we were able to peer through the snow and see under the surface of the soil, we'd see their little neon lights glowing. These firefly larvae, aptly nicknamed glow worms, burrow into the ground for the duration of winter. When they emerge in spring their soft greenish-yellow glow will dot the forest floor.

And those pesky mosquitoes? What are they doing now? Most are spending the winter as eggs in wet vegetation, ponds, and other bodies of water. Some species, though, spend the winter as adults and are still flying about - like the one I saw in my office last week who met her premature demise. The fertilized females of the northern house mosquito come indoors for the winter. Having already mated, they've got a head start on things come spring when they immediately lay eggs - and then, of course, the next generation invades our houses for midnight snacks in the summer.

Frogs and turtles spend the winter underground below frost-line. No matter how cold it gets above ground, they are protected deep in the mud. Snakes may gather in logs or underground shelters called hibernacula. It's pretty cool to see a dozen garter snakes emerge from a hibernaculum on an early spring day. Their mass slithering is kind of like in the movies, but not scary. These are just garter snakes.

It's a cold, cruel world in the winter months. It's tough out in the wild, and thus the critters must be as well. Their survival strategies are as varied as the animals themselves. Perhaps, like us, they are getting cabin fever about now. We all want out!

When this long winter is over, our wildlife will eagerly crawl, slither, dig, emerge, and spring to life again. There is light at the end of the snow tunnel!

Valerie Blaine is the nature programs manager for the Kane County Forest Preserve District. She overwinters wearing many layers, searching snowdrifts and exploring the frozen tundra of Kane County. You can reach her by wolf howl across the prairie or by e-mail at blainevalerie@kaneforest.com.

<p class="factboxheadblack">Some possible cures for cabin fever</p> <p class="News">If you've been cooped up too long in a state of hibernation, break free and get outside! There are many opportunities to enjoy the forest preserves in winter.</p> <p class="News">• Tekakwitha Woods Nature Center: Check out Tekakwitha Woods Nature Center with its interactive displays and hands-on activities. The nature center is at 35W076 Villa Marie Road in St. Charles. It's open from 1-4 p.m. Saturdays and Sundays and 9 a.m. to 4 p.m. Mondays and Wednesdays.</p> <p class="News">• "Wetlands in Winter": Come along on a guided hike at the Dick Young Forest Preserve from 10 to 11:30 a.m. Saturday, Feb. 14. Naturalist Jaclyn Olson will lead this exploration of the wetlands in winter. All ages are welcome.</p> <p class="News">• "Little Acorns": Children ages 4 and 5 are welcome to "Little Acorns" on Thursday, February 19, from 10 - 11 a.m. and 1 - 2 p.m. This hourlong nature program features stories, games, a simple craft and a short nature hike.</p> <p class="News">• "Land of Lichens": Adults can learn about the fascinating world of lichens during this class at Tekakwitha Woods Nature Center from 1 to 3:30 p.m. Saturday, Feb. 21. Led by lichenologist Rich Hercyzk, this presentation is sure to open up a whole new world of beautiful life-forms.</p> <p class="News">For information about these programs and other forest preserve district activities, call (847) 741-8350 to register or e-mail <a href="mailto:programs@kaneforest.com">programs@kaneforest.com</a>.</p>