Listen to a windblown pine tree and hear the winter song, or stand near a red oak tree still clinging to some of its brown-colored leaves from last fall. The rustling leaves have the sound of a summer rainfall. On bitter cold days, birds puff out their feathers for more insulation. Black-capped chickadees, blue jays, northern cardinals and others are interesting to watch at feeding stations — and a reminder that life outlasts every winter.

The sunlight in December and January casts the longest shadows of the year. The dark tree shadows on white snow are spectacular. Fresh snow reflects close to 90% of the sun's radiation from its surface, and the intensity of sunlight is now just a quarter of the maximum level we had back in June. No wonder we experience cold days.

The days are short and the nights long, but we are gaining about two minutes of daylight each day. We often experience a warmer period or periods known as "January thaws." If it happens, look for mosses that will be lush green and growing, honeybees out on cleansing flights, bicycle use on the upswing, and runners out in shorts. Some raccoons may wake from their winter sleep.

Whitetail deer are browsing twigs from sugar maples, basswoods and white cedars. Healthy deer will eat about six to eight pounds of twigs daily. Bucks continue to drop their antlers since the rutting season ended in about mid-December. The bucks in the finest condition and having the largest racks are usually the first to drop their antlers. Many people are not aware that bucks shed antlers because they have never found antler sheds, often covered with leaves and snow. Mice, squirrels and other animals gnaw them because of their high calcium and phosphorus content, so by summer most of the antlers have been consumed, their minerals a part of other animals. At one time the students and I watched as a buck shed an antler while eating seeds from a platform bird feeder outside the lunchroom at Lowry Nature Center. We drilled a hole through the antler, hooked a wire between it and the base of the feeder, and over the next several weeks watched the mouse and squirrel tracks in the snow, the rows of gnawing, and the antler disappearing.

Shortly after sundown, eastern cottontail rabbits are active foraging on the bark and twigs of shrubs. In northern Minnesota, ruffed grouse dive into powdery snow to keep warm at night. Porcupines are active all winter, feeding on the bark of trees. Also, snowshoe hares are wearing their white winter coats and blend into the snow, making it difficult for bobcats and other enemies to find them.

Jim Gilbert's observations have been part of the Minnesota Weatherguide Environment Calendars since 1977, and he is the author of five books on nature in Minnesota. He taught and worked as a naturalist for 50 years.