American Goldfinch has a partial preformative molt and a partial prealternate molt. Sex can generally be identified by plumage throughout the year, although the difference between males and females is more subtle in winter and as juveniles.
Age and plumage cycle can usually be determined reliably throughout the year. However, caution is required from late summer to mid-fall (primarily August to October), when the prejuvenile, preformative, and prebasic molts of individuals in a population may overlap. During this period, four age classes (HY, SY, AHY, ASY), four active molt categories (FPJ, FPF, SPB, and DPB), and five plumage categories (FCJ, FCF, FCA, DCB, and DCA) may be possible concurrently. The presence of alternate plumage (e.g., black cap and bright yellow body on males) and the extent of feather wear are particularly important clues during this period.
Species account prepared by McGill Bird Observatory (2016). Last updated by Marcel Gahbauer (Mar 2022)
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FCJ - (HY: June - October) | |||
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Generally beige to brown body, with buff wing bars; sex often not reliably distinguished, but (M) with darker wing and more distinct white patches on outer rectrices than (F) | |||
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FCF - (HY: September - December; SY January - June) | |||
Greater coverts black (M) or dark brown (F), contrasting with somewhat paler primary coverts; rectrices blackish (M) or brownish (F) and fairly pointed, with white (M) to whitish (F) patches often having poorly defined edges | |||
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FCA - (SY: February - November) | |||
Greater coverts black (M) or dark brown (F), contrasting with somewhat paler primary coverts; rectrices blackish (M) or brownish (F) and fairly pointed, with white (M) to whitish (F) patches often having poorly defined edges | |||
F |
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DCB - (AHY: August - December; ASY January - June) | |||
Wing feathers uniformly black (M) or dark brown (F), not contrasting notably with primary coverts; rectrices black (M) or dark brown (F), fairly broad and rounded, and usually with sharply delineated white patches (M) or moderately distinct whitish patches (F) | |||
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DCA - (ASY: February - November) | |||
Wing feathers uniformly black (M) or dark brown (F), not contrasting notably with primary coverts; rectrices black (M) or dark brown (F), fairly broad and rounded, and usually with sharply delineated white patches (M) or moderately distinct whitish patches (F) | |||
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F |
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FPJ - (HY: June - September) | |
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Similar to FCJ; some natal down remaining and/or juvenile flight feathers still growing in | |
No images available yet | |
FPF - (HY: September - December) | |
Similar to FCF; some to all median coverts, some to all greater coverts, and occasionally the central tertial being replaced | |
No images available yet | |
FPA - (SY: February - July) | |
Body feathers being replaced, with yellow feathers growing in; up to six inner greater coverts and occasionally the central tertial being replaced | |
No images available yet | |
SPB - (SY: August - December) | |
Flight feathers being replaced, with retained juvenile primaries, secondaries, and/or primary coverts distinctly brownish and quite worn | |
No images available yet | |
DPB - (AHY: August - December) | |
Flight feathers being replaced, with retained primaries, secondaries, and/or primary coverts either distinctly adult (generally dark and less worn) or intermediate | |
No images available yet | |
DPA - (ASY: February - July) | |
Body feathers being replaced, with yellow feathers growing in; occasionally also up to two inner greater coverts being replaced | |
No images available yet |
Molt classes | Age | Months | Key traits |
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M-FPF / UPU (FPF, SPB, DPB) | U | July - September | Undergoing preformative or prebasic molt, but cycle is not reliably distinguishable |
M-FCF / UCU (FCF, SCB, DCB) | U/AHY | July - March | In formative or basic plumage (molt completed), but cycle is not reliably distinguishable |
M-FPA / UPA (FPA, DPA) | AHY | February - April | Undergoing prealternate molt, but cycle is not reliably distinguishable |
M-FCA / UCA (FCA, DCA) | AHY | February - August | In alternate plumage (molt completed), but cycle is not reliably distinguishable |