When we think of birds and winter, we usually think of birds flying south to warmer weather. But look out the window right now and you might join poet Catherine Bowman in her subzero poem “House Arrest” when she says, “we’ll bicker with the birds / over scraps of weather / and the privilege to sing.”
The black-capped chickadees are privileged to sing in the winter because they have been engineered to withstand freezing temperatures. They may be tiny, but they are not frail. Their first line of defense is their feathers. Fluffed and oily, their feathers serve as a remarkable layer of insulation and waterproofing. Further, they gorge themselves during the day on insects, insect eggs, and seeds to increase their body fat; and at night, they can regulate their body temperatures by lowering their metabolism and going into a voluntary hypothermia to conserve energy. Even with this conservation of energy, on cold nights, chickadees can burn virtually all the body fat they store during the day, shivering to stay warm during the night.
Can we help our tiny, marvelous neighbors? Scientists have noticed that during milder winters, chickadees do not depend entirely on backyard feeders, but will supplement about 25 percent of their foraged diet with food from feeders, if it is available. But, during particularly harsh winters, when the temperatures dip below -10°F, chickadees with access to a supply of backyard bird feeders are more likely to survive.
So, while we are snug inside our hotels or houses, with slippers and fireplaces to keep us warm when cold winds whip off the lake, and we hear the cheery chatter of the chickadee, we should consider setting out a handful of sunflower seeds, their favorite fatty snack.