By Lee FranksChickadees are named after their husky calls, typically a high, thin, scratchy “tseck-a-dee-dee.” They belong to the order Passeriformes (perching birds), and are in the Titmouse family (Paridae). There are about 65 species of titmice in the world, and all are small, perching birds with soft fluffy plumage, usually in grays and browns.
The Chestnut-backed Chickadee, Poecile rufescens, is most common along the Pacific Coast regions, and is believed to be the smallest member of its family, measuring 4-5″ long. Unlike most chickadees (there are 7 North American species, 4 of which are found in the Pacific Northwest), the Chestnut-backed has no whistled song, but uses gargle or clicking notes instead.
The back, sides, and rump are a deep rufous-chestnut that contrasts with the white of their underparts. Their cap, from forehead to hindneck extending to just below their eyes, is blackish, bordered below by a white cheek patch. The throat and upper breast is a blackish-brown, in sharp contrast to a white lower breast. Their wings are brownish gray with white edging. The tail is also brownish gray, but the edging is pale gray. Males, females, and young all look alike.
Chickadees are active birds that constantly hop about in the outer branches of Edgewood’s oak trees. They especially like clinging upside down to a twig or making short flights from tree to tree. These flights are usually done when feeding and are best described as a slow bobbing flight. They are able to perform remarkable acrobatics as they glean insects, as well as their eggs and larvae, from leaves, twigs, branches, and bark.
During the breeding season they are territorial, but they join mixed-species flocks in the winter. Territories often adjoin those of the Oak Titmouse, with which the chickadee competes for nest sites, and, to some extent, food. Chickadee nests are 50% hair and fur. The most common hair they use comes from deer, rabbits, and coyotes. The adults make a layer of fur about a centimeter thick which is used to cover their eggs whenever they leave the nest.Chestnut-backed use nest boxes in the park when they can’t find a more suitable place to build their nests. Since they are year-round residents, they usually make use of boxes in winter to serve as a winter roost to conserve heat. By grouping together in a small space they are able to use their escaping body heat to warm the air around them, thereby saving a great deal of metabolic energy. This type of prolonged contact increases the likelihood of transmitting parasites and diseases between the birds. But the benefit of sharing body heat must outweigh the potential health risk.
Chickadees are small, but they are social and they work together to fight predators. They believe that there is strength in numbers. When a chickadee spots an owl, hawk, or other predator perched nearby, it makes a warning call that sounds like its name (“chick-a-dee-dee-dee.”) Other chickadees within earshot then swarm together and mob the predator, usually harassing it so that it flies away.
Scientists have found that not only do chickadees use vocalizations to coordinate predator behavior, they actually have different calls for different predator situations. Chickadees that spot approaching predators give high-pitched “seet”calls and flee. They also seem to vary their “chick-a-dee-dee” alarm calls in order to send slightly different warnings. For example, the “dee-dee” call becomes longer or shorter, depending on the size of the predator. Small raptors are actually more dangerous to chickadees than large ones, because they are more agile and better able to catch tiny birds. The big beaks and talons of the large raptors are only useful if the bird can catch its prey. Chickadees can turn on a dime, so the smaller raptors have a better chance of catching them.
So, the number of “dees” at the end of chickadees warning call sends a message to other birds in the flock about how dangerous the nearby predator is.
The Birds of North America, No 689, 2002; Donald L. Dahlsten, Leonard A. Brennan, D. Archibald Mccallum, Sandra L. L. Gaunt.