Chestnut-backed Chickadee

Fairly common in wooded areas throughout the county, including residential areas, but mostly stays in the more humid coastal forests rather than the drier country inland where this bird is confined to canyon bottoms and other pockets of favorable habitat. Common feeder visitor in suburbia. Often travels in small flocks, sometimes in mixed flocks of other full-time residents (Oak Titmouse, Bushtit, vireos, and nuthatches) and with warblers during migration. Looking for chickadee flocks is, in fact, a well-known strategy for finding unusual warblers in the spring and autumn. Nests in naturally existing cavities or abandoned woodpecker holes. Also uses net boxes. Can be quite acrobatic, feeding while hanging upside down or sideways, exploiting resources overlooked by other common woodland birds. Mostly eats insects but will eat seeds and berries. Fond of suet as well. Sometimes quite tame near parks or feeders. Older sources will list this bird as Parus rufescens. Often noisy, especially when in flocks. Says shik-a-jee-jee in a high, thin voice compared with Oak Titmouse, which makes similar sounds but in a somewhat louder, lower-pitched, huskier voice.

The only chickadee regularly present in Sonoma County. Distinguished from other chickadees by its rufous back and sides, although subspecies to the south of us have comparatively little of the chestnut color on their sides. Three subspecies are recognized. Poecile rufescens rufescens, found from Alaska south to northwestern California and east to Montana, has the most obvious rufous on the flanks (like the bird above). P.r. neglectus, with narrow, pale rufous bands on the flanks, is confined to southern Marin County. (This subspecies may have been lost to interbreeding with P. r. rufescens populations that have moved south from Sonoma County comparatively recently, according to Lukas.) P. r. barlowi, found in coastal southern California (from San Francisco south), has very little rufous on the flanks at all. The bird in the photo below was photographed in Sonoma County (Santa Rosa) but it is plain grey on the flanks. This may also be P. r. barlowi. It is in any case atypical for the county. Our birds are mostly of the P. r. rufescens subspecies, with unambiguously chestnut sides, as in the main photo above.