Lesser Goldfinch, Carduelis psaltria
Lesser Goldfinch, male, 9/3/08, Russian River, Healdsburg, Sonoma Co
These are the most common Bay Area goldfinches, regulars in our yard year-around. The male has a black cap and brighter yellow on the underparts. The back on both sexes is olive with more or less gray, by contrast to the black backs on the males of the subspecies found in Texas, the Rockies, and south of the border. Arizona and New Mexico males are intermediate between the two extreme forms; apparently females, like the Arizona female just below, do not show regional variation in plumage.
Lesser Goldfinch, female, 8/2/08, Madera Canyon, AZ
Lesser Goldfinch, adult female, 1/11/04, Arastradero Preserve
Left, a bright female -- compare the paler one directly below, and the intermediate one above.
Lesser Goldfinch, female, 2/21/09, McLellan Ranch Park, Cupertino
Lesser Goldfinch, female, 2/19/09, Rancho San Antonio, Los Altos
Lesser Goldfinches are said to have yellow undertail coverts, as distinguished from the white ones of American Goldfinch, but the yellow can be quite pale, verging on white, as in the female left and the male below.
Lesser Goldfinch, male, 2/19/09, Rancho San Antonio, Los Altos
Lesser Goldfinch, first summer male, 7/2/06, my back yard, Stanford campus
I think the birds left and below are first-summer males, about a year old. The head shows some black, distinguishing it from the adult female, and there's less color than in the adult male -- the yellow on the underparts is paler, and the back looks gray rather than olive. West Coast Lesser Goldfinches such as these  have only one annual moult, according to Birds of North America Online; the summer plumage is the basic, heavily worn.
Lesser Goldfinch, male,  8/27/06, my back yard, Stanford campus
Lesser Goldfinch, male, 2/21/09, McLellan Ranch Park, Cupertino
Lesser Goldfinch, male, 1/29/06, back yard, Stanford campus
Lesser Goldfinch, male, 9/14/08, Frenchman's Park, Stanford campus
Lesser Goldfinch, male, 2/21/09, McLellan Ranch Park, Cupertino
Lesser Goldfinches have a white patch at the base of the primaries, notable in the bird with the fanned wing feathers above, but visible on perched birds as well, see left.
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