Winter is very hard on small birds. They must eat enormous volumes of food to sustain their active metabolisms. Chickadees eat 20 times more food during cold weather than in the summer. Long, bitter winters can kill off 80 percent of a chickadee population in an area. To survive black-capped chickadees conserve energy in severe cold weather by lowering their body temperature at night and entering regulated hypothermia. They can (drop)their body temperature at night by 20 degrees below their daytime internal temperature of 108 degrees. This conserves a modest supply of fat so that they can start the new day.
Chickadees can also shiver, which helps keep them warmer, but they need to soon replenish their fat with high energy food or they will die. When the temperature drops to minus 20 degrees, they stop feeding because it takes more energy to find food than to wait for warmer weather. A roosting box that provides shelter from cold wind and snow can be a life-saver for these wonderful birds.
Feeding In the Landscape
Chickadees roam the yard during the winter in flocks of five to nine birds hunting for protein and fat in the form of insect eggs and larvae and seeds from the plants in the area. Half the black-capped chickadees’ winter diet is seeds of hemlocks and other conifers, cone-bearing needled evergreens. They also dine on suet from carcasses of dead deer and poison ivy berries (which, unfortunately, they inadvertently distribute throughout the neighborhood).
At the Feeder
Chickadees consume only 20 to 25 percent of their energy requirements from backyard feeders, but this can make a survival difference. They flock to yards where thoughtful homeowners provide high fat food in the form of sunflower seeds, peanut kernels, and suet blocks. From the kitchen they love stale doughnuts, piecrust, popped popcorn, nut meats, and melon seeds, and even stale doughnuts to help them survive the winter. Once in the habit, they will continue to visit over the summer as well if food is provided. They will visit almost any kind of bird feeder, taking only one seed at a time, flying to a perch and eating it. Then they return for another. They also visit peanut butter feeders. Mix the peanut butter with suet and cornmeal.
Chickadees especially like and both striped and black oil sunflower seeds. In mild winter weather, they need the energy equivalent to 150 sunflower seeds a day to stay alive. When the temperature drops to zero degrees, they need the equivalent of 250 sunflower seeds daily--roughly 60 percent of their body weight.
For a discussion of bird feeders appropriate for chickadees go to Yardener's Tool Shed; click here