chickadee (chĭkˈədēˌ) [key], small North American bird of the titmouse family. The black-capped chickadee ( Parus atricapillus ), lively and gregarious, is a permanent resident over most of its range in the East. Both sexes have black caps, gray backs and wings, and fluffy white to buff underparts. They often swing upside down from branch tips, searching for the insects that form more than half their diet. Their call note gives the bird its name. Other species are the Carolina, the boreal, or brown-capped (of the Northeast), and the western chestnut-backed chickadees. Chickadees are classified in the phylum Chordata, subphylum Vertebrata, class Aves, order Passeriformes, family Paridae.