Chickadees are small, round, ½ oz. energetic birds that frequent feeders and forests across North America. There are several different types of chickadees in the United States. The Boreal chickadee predominates In the northernmost regions of Maine and Canada, while the Carolina chickadee lives in the mid-Atlantic and southeastern United States. However, the ones you’ll find at Hirundo are Black-capped chickadees. Their range extends across much of the northern United States and Canada. The traditional “chickadee-dee-dee” call we associate with chickadees comes from the Black-capped chickadee. These birds are a year around resident here in Maine, and they frequently make their presence known with their cheerful call. Because they do not migrate long distances, they lack the long, sleek, primary feathers necessary for long distance migration.
So what is their secret to persisting here in the winter? Several traits allow chickadees to survive short days, wind, snow and bitter cold:
Food as fuel! Chickadees eat high-energy seeds, insects and other fatty substances like suet. During the summer and fall, they store food in any natural crevice they can find. At the bird feeder, they take sunflower seeds and fly away to store them, then return for more. One truly amazing adaptation chickadees have is their memory. They are able to recall where they’ve hidden almost all their food. The part of their brain used for spatial memory regenerates each year as new information is stored. When the winter is over, those nerve cells die, erasing the knowledge of their previous hiding spots and creating room for more.
Chickadees can drop their high body temperature at night to save energy. In the morning they shiver - activating their muscles to increase body heat again. At night, protection from the elements is also important. Squeezing into tight places in trees reduces exposure. About 10% of a chickadee’s body weight is lost each night, so they must regain that fat the next day. That explains why they always seem so busy searching for food! Birds molt in the fall, adding up to 25% more insulating down feathers to prepare for the winter ahead. Just as we put on a down coat to keep warm, chickadees do the same! But what about a chickadee’s featherless legs and feet? Why don’t they freeze? The warm blood circulating within their body transfers some of its heat to their exposed limbs, keeping them sufficiently warm. If necessary, they can stand on one leg and draw up the second near their body to warm it.
Other traits that chickadees have developed include large clutch sizes - nine eggs in a nest is not uncommon. Each hatchling weighs only one gram - about as much as a paper clip! Within the next several weeks after hatching, they grow to about 11 grams. With large numbers of offspring, the parents are more likely to have one or two young that will survive to replace them.
Another thing chickadees do to survive the winter is form small flocks. During the mating season, pairs work together to feed and take care of their young within their own defended territory. In the winter, they move together in groups of about a dozen to gather food and keep an eye out for predators. More eyes offer better protection! If you listen carefully, you can hear their constant communication. By varying their calls, they can signal the presence of either a stationary predator or a moving predator, as well as indicate its size. Up to 25 different calls have been recorded.
All this activity takes its toll. A chickadee’s lifespan is typically only two to three years. In captivity, some have lived for nearly 10 years. Males and females appear identical, but they behave differently. Males feed the females while they build the nest and incubate the eggs. Chickadees prefer to live at the edge of woodlands, where a variety of food is available. Nesting often takes place in excavated cavities within rotting birch and alder trees. They make new nests each year, leaving their old ones behind to be overtaken by other birds. Chickadees will occupy bird houses, and especially prefer wood shavings substrate at the bottom.
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