The Carolina chickadee is quite at home in cities and towns, readily using nest boxes and bird feeders. In fall and winter, the Carolina forages in mixed flocks with nuthatches, woodpeckers, warblers, and other woodland species. The only chickadee in the Southeast, the Carolina is smaller and duller than most other chickadee species. Polytypic. Length 4.8".
The cap and bib are black; the cheeks are white, usually tinged at rear with pale gray; the back and rump are gray, sometimes with an olive wash; the greater coverts are gray without pale edgings; the secondaries and tertials are indistinctly edged in dull white or pale gray; the flanks are pale grayish, tinged buffy when fresh in fall.
Four subspecies—largest and palest on upperparts in western portions of the range; smallest and darkest in Florida. Differences are weak and clinal where ranges meet. Subspecies are not field-identifiable.
The absence of white wing edgings on greater coverts and the grayish wash on flanks, even when slightly tinged with buff, help to separate it from the black-capped. The Carolina interbreeds extensively in some areas with the black-capped along a belt from Kansas to New Jersey; the hybrid offspring are not easily identifiable. Paler sides and flanks distinguish it from the mountain chickadee when the usually conspicuous white supercilium of the latter species is not visible.
Call: a fast and high-pitched chick-a-dee-dee-dee. Compare to black-capped’s call. Song: a 4-note whistle, fee-bee fee-bay, the last note lowest in pitch. A Carolina may learn the black-capped’s 2- or 3-note song in areas where their ranges overlap, so do not identify by song alone at the contact zone.
Status and Distribution
Common. Year-round: open deciduous forests, woodland clearings and edges, suburbs, and urban parks; in the Appalachians it prefers lower elevations than the Black-capped, but it has been recorded regularly as high as 6,000 feet. Vagrant: wanders casually short distances north; single records in Michigan and Ontario are extraordinary.
Apparently declining in some regions in recent decades, particularly in the Gulf Coast states, but its range has expanded northward along much of the contact zone with the black-capped, particularly in Ohio and Pennsylvania.
—From the National Geographic book Complete Birds of North America, 2006