American Robin has a partial preformative molt but no prealternate molts. Although a common species, American Robin can be challenging to age and sex due to a high degree of individual variability. Although extremes are readily identifiable, many individuals are not reliably sexed by plumage, and by spring ageing can also become particularly challenging and should be done only if key characteristics are distinct and consistent.
Species account prepared by McGill Bird Observatory (2016). Last updated by Marcel Gahbauer (Mar 2022)
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FCJ - (HY: May - September) | |||
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Upperparts spotted; underparts with moderate to heavy dark mottling | |||
U |
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FCF - (HY/SY: July - following September) | |||
Rectrices relatively dull brown and narrow; outer greater coverts shorter than inner coverts and sometimes with buffy-white shaft streaks; breast often with some gray mottling, especially on females; crown generally brown (F) to mottled dark brown to blackish (M) | |||
M |
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F |
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DCB - (AHY/ASY: July - following September) | |||
Rectrices relatively dark and broad; greater coverts uniform in length and freshness; breast mostly orange with some gray (F) or solid dark orange (M); crown generally mottled dark brown and blackish (F) to solidly blackish (M) | |||
M |
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F |
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FPJ - (HY: May - 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: July - October) | |
Similar to FCF; most to all median coverts and up to most greater coverts being replaced; sometimes also one or two tertials | |
No images available yet | |
SPB - (SY: July - September) | |
Flight feathers being replaced, with retained juvenile primaries, secondaries, and/or primary coverts distinctly pale brownish and worn | |
No images available yet | |
DPB - (AHY: July - September) | |
Flight feathers being replaced, with retained primaries, secondaries, and/or primary coverts either distinctly adult (relatively dark and not overly worn) or intermediate | |
No images available yet |
Molt classes | Age | Months | Key traits |
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M-FPF / UPU (FPF, SPB, DPB) | U | July - October | Undergoing preformative or prebasic molt, but cycle is not reliably distinguishable |
M-FCF / UCU (FCF, SCB, DCB) | U/AHY | January - December | In formative or basic plumage (molt completed), but cycle is not reliably distinguishable |