Animals in Winter
Trees are bare and lawns are brown. Woodlands and marshes teaming with wildlife only a few months ago are comparatively still. But don’t be fooled by appearances. Beneath winter’s frigid mask, many animals, large and small, have adapted to the seasonal changes in temperature and light in a way that is quite remarkable. A walk through a sanctuary reveals tracks and traces of animals successfully surviving another Connecticut winter.
While humans prepare for the cold by bringing out winter clothes, turning up the thermostat and lighting the fireplace, animals begin their preparation for winter during the late summer while many of us are still gathered around the barbecue. Subtle changes in daylight and temperature signal the beginning of activities that will determine an animal’s successful transition or adaptation to the winter season. There are basically four ways in which animals spend the winter. They might migrate, hibernate, catnap or remain active.

Migrators
Migration is when animals move from one place to another with regularity. It may be from the north to the south, from the west to the east or simply, from the top of a tree to below the frost line. The reason for migration is not necessarily temperature (many birds have insulating feathers, which could keep them warm throughout the winter). Food is the prime motivation for animals to migrate to other locations where sources are more readily available.
For instance, hummingbirds sip nectar from flowers. Most flowers can not survive cold temperatures. Thus, hummingbirds migrate to Central America in the fall seeking a locale with more plentiful food supplies. Some northerly birds even migrate south to Connecticut when their food supplies run out. Some years, evening grosbeaks fly from the north to feast at backyard feeders throughout the state. Birds that enjoy Connecticut winters are crossbills, juncos, pine siskins and tree sparrows, among others.

Hibernators
Another way animals beat the cold and lack of food is by taking a long winter nap. There are only three mammals that hibernate in Connecticut; little brown bats, woodchucks and jumping mice. Hibernation requires them to eat tremendous amounts of food in the fall to build up a thick layer of fat that will be their energy source throughout the winter. By the spring, when they have used up all their stored fat, they will wake up from their multi-month slumber and be quite thin. A hibernating woodchuck’s heart rate drops to almost nothing, breathing about once every six minutes. It’s dormant and dead-like state lowers its body temperature and blood pressure to very low levels.
Unlike mammals, cold-blooded animals such as reptiles and amphibians, enter a deathlike state called a torpor. To survive the winter, frogs, toads, snakes and turtles sleep away the winter underground beneath logs, mud or soil where they will not freeze. Snakes often spend the winter in decaying logs, chipmunk holes, rock crevices or basements. Venomous and non-venomous snakes may even den up together, looking like a ball of yarn.

Catnappers
Other Connecticut animals are categorized as "catnappers" who don’t sleep the whole season away but take extended naps only during the coldest weeks. Unlike hibernators, the heart rate and blood pressure of catnappers does not slow down and they awaken easily at any time.
Chipmunks, skunks, raccoons and opossums are in this category and they will snooze in any cozy burrow they can find or make. Chipmunks store their food with them underground but others do not and will emerge to rummage the winter landscape for food.

Active Animals
Even during the coldest months of the year, there are many animals that are quite active throughout the winter including squirrels, moles, mice, shrews, beavers, muskrats, rabbits, weasels, deer, foxes and birds. In order to keep warm, some mammals grow a new winter coat, up to three layers thick, preventing air or snow from reaching their skin.
Some active animals grow a different colored coat of fur to blend in with the landscape helping to conceal them from predators. Animals that live in the water during the winter, like muskrats or beavers, have an oily outer coat so water rolls right off them. Ducks, geese and swans have little sacs of oil near their tails. They reach back with their bills to this sac and spread a thin layer of oil on their outer feathers so they are waterproofed. Then the "water rolls off a duck’s back".
Birds keep warm by fluffing out their feathers giving them a plump, round appearance. This fluffing creates pockets of "dead air" that keep cold air from passing through to their bodies. Birds are quite skilled at seeking out berries and dormant insects as well as other natural food sources from the winter landscape. Birds often get an additional bonus during the winter when they come across birdseed put out for them at backyard feeders. Other animal species are not nearly as fortunate to enjoy such a prepared meal!

Although the majority of insects spend the winter in a state of suspended animation called diapause, there are some insects such as sowbugs, pillbugs, springtails and spiders that remain active throughout the winter insulted from the cold beneath layers of vegetation. Also, as this vegetation begins to decompose, it gives off heat. Snowfall often adds another protective layer.

Honeybees remain active throughout the winter. The members of the hive work together to keep each other warm. One hive may consume 30 pounds of stored honey over the winter months. The bees "burn off" the honey they have eaten by vibrating their wings. This exercise generates heat, which may keep the hive as warm as 90 degrees Fahrenheit at the center.

A walk in the winter woods often reveals that there is more going on there than meets the eye and that you are never truly alone. Animal tracks imprinted in the snow prove that throughout the winter, activity and movement abound. Animals in winter provide fascinating examples of unique and interesting adaptive behaviors. For more information regarding nature during the winter months refer to A Guide to Nature in Winter written by Donald W. Stokes and published by Little, Brown and Company.

Archived from CT Audubon Society News Copyright Connecticut Audubon Society Reuse by Permission Only