The mountain chickadee (Poecile gambeli) is a small songbird, a passerine bird in the tit family Paridae. Often, it is still placed in the genus Parus with most other tits, but mtDNA cytochrome b sequence data and morphology suggest that separating Poecile more adequately expresses these birds’ relationships. The American Ornithologists’ Union has been treating Poecile as a distinct genus for some time.

Mountain chickadees are known colloquially as cheeseburger birds, as their call sounds like they are saying “cheese-bur-ger.”

Adults of both sexes have a black cap joining a black postocular stripe behind distinctive white eyebrows. Their backs and flanks are gray and they have paler gray underparts; they have a short black bill, and a black bib. The typical adult wingspan is 7.5 in (19 cm), and the overall length is 5–6 in (13–15 cm).

Ref: Mountain Chickadee Information