chickadee (CHIK-uh-dee) - n., any of several small plump North American birds of the genus Poecile with predominantly gray plumage and a dark crown.
Especially P. atricapillus, the black-capped chickadee:
There are seven species in all, and they are close relatives of tits (or titmice, as they are called in North America). Very cute birds, very bold, and readily adapted to urban areas. They do not migrate, which means they visit backyard feeders throughout the winter. They are named imitative of its call: chick-a-dee-dee-DEE, with the last note louder and distinctly higher.
I've always been disappointed that the "Chickadee Tidbits" advertising jingle from Edward Eager's Seven-Day Magic has never been real.