It is still often 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 (Gill et al., 2005).

The American Ornithologists' Union had been treating Poecile as distinct genus for some time already.

Although primarily nonmigratory, Mexican chickadees sometimes fly to lower elevations during the cold of winter.

The nest is constructed by the female in a snag or tree cavity up to 18 m above the ground, and consists of grasses, moss, strips of bark, and is lined with animal fur.

She lays between five and eight ovate white eggs, marked with fine reddish brown spots.