Distinguishing Characteristics

Adult female American Goldfinch, breeding plumage, NY, July

Female American Goldfinch, NY, October

Adult male American Goldfinch, non-breeding plumage, IA, November

Small (11.4–12.8 cm), sexually dimorphic finch, with small conical bill and short notched tail. Males slightly larger and, in nonbreeding season, heavier than females (Wiseman 1975 , Middleton 1977a , Prescott 1983 , Pyle et al. 1987 ). Body mass varies with season: summer 11.0–13.0 g; winter 13.5–20.0 g (Carey et al. 1978 , Middleton 1982 , Prescott 1983 ). Sexes separated by plumage in all seasons but differences marked in spring and summer.

Juveniles brown above, pale yellow below, shading to buff on sides and flanks; throat of males progressively brighter yellow with age (Middleton 1977b ); flight feathers dark blackish-brown, males darker than females; wing bars and feather tips buffy.

Adults in Basic plumage olive brown above, olive yellow below, shading to buff on sides and flanks; males have brighter yellow throats, jet black flight feathers, yellow or olive yellow lesser coverts, black greater coverts, tipped white; females have blackish brown flight feathers, olive lesser coverts, blackish greater coverts tipped white or buff.

Adults in Alternate (Breeding) plumages: Male lemon yellow; cap (including the forehead, crown, and lores) jet black; wings also jet black, white tips worn; wing coverts yellow with greater coverts white tipped; tail black, white on inner webs; bill orange, legs and feet light brown. Females “brighter” than in Basic plumage; brownish olive on back, greenish yellow on forehead, throat, abdomen and rump; sides and flanks buff; wings and tail blackish brown, worn tips; white on inner webs of tail; bill dull orange, legs and feet dusky brown.

Adults vary within each sex in the coloration of Basic and Alternate plumages, both in the purity (or “saturation”) of the yellow plumage and orange beak and in the size and symmetry of the black cap (McGraw and Hill 2000, 2001, Macdougall and Montgomerie 2003, McGraw 2004, Rosen and Tarvin 2006).

Female-plumaged Lesser Goldfinch (C. psaltria ) and Lawrence’s Goldfinch (C. lawrencei ) are sometimes confused with female American. Both are slightly smaller, and have a different tail pattern: on the American, white patches on the inner webs of outer rectrices extend out to tip of tail; on Lesser and Lawrence’s, white spots are centered on the tail and the tips of the rectrices are solidly dark. Lesser Goldfinch has yellow undertail coverts (white on American), while Lawrence’s differs from both in having rich yellow wingbars (Kaufman 1993 ).