Some wildlife escapes winter by heading south - but other birds and animals stay put and have special systems for coping with the cold.The only total escape from winter, George Harrison wrote in an article in Sports Afield, is to change locale.
Whales, bats, many birds and monarch butterflies are among those that migrate to warm climates. Animals such as elk and mountain goats move to lower elevations. Animals such as woodchucks and snakes hibernate in a burrow, while frogs, toads and turtles move to the bottom of a pond. The rest of the wildlife endures winter with special techniques.
A ruffed grouse careens around a white pine at a speed in excess of 40 mph, swoops over a snow-covered log, folds its wings and dives into the snow. Two feet under the soft stuff, it settles into one of nature's great winter escapes. The temperature inside the cozy roost is 52 degrees Fahrenheit warmer than outside.
To keep warm, many animals eat a great deal more during winter. The goshawk will eat a ruffed grouse or a small animal about every day during winter to obtain enough energy to survive the cold. Black-capped chickadees, American goldfinches and northern cardinals eat 20 times more food on a winter day than in summer.
Songbirds also grow 20 percent to 30 percent more feathers in winter; by fluffing them to trap the warm air, they conserve heat. When necessary, they shiver to produce more heat.
During long winter nights, birds may put themselves into hypothermia, dropping body temperatures by 20 degrees and slowing their heartbeats. Their exposed legs and bills, like a beaver's hairless tail, do not freeze because surface veins carry blood to where warmer arteries act as heat exchangers.
Some wildlife keeps warm in communal roosts. As many as 24 male eastern bluebirds have been found in the same birdhouse, 12 acorn woodpeckers were discovered in a tree cavity and 21 raccoons were seen sleeping together in Minnesota.
Short-tailed shrews and bears are among those mammals that store "brown fat" over their shoulder blades. When cued by the cold, the fat is converted to heat.
White-tailed deer may eat less during winter - it takes energy to find food in deep snow. Their coats of hollow hair are four times denser in winter and are such good insulation that snow doesn't melt when it falls on their backs.
Warm-water fish beat the cold by retiring to the warmest and deepest water and remaining relatively inactive. Though bluegills, bass, perch and crappies may take bait offered through the ice, they generally don't eat much, move very little and use less oxygen.
Bullheads and carp become totally dormant, digging into the bottom mud and sleeping through the winter or in a state of reduced respiration. Cold-water species - northerns, muskies and trout - remain active throughout the winter and probably eat more often.