Red-breasted Nuthatch has a partial preformative molt and absent to limited prealternate molts that are difficult to detect. Plumages differences by age are subtle, and especially by spring, many intermediates are difficult to age precisely. However, sex can be readily distinguished by plumage throughout the year.
Species account prepared by McGill Bird Observatory (2018). Last updated by Marcel Gahbauer (Mar 2022)
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FCJ - (HY: June - August) | |||
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Yellowish to whitish gape; some speckling on head and throat; crown gray (F) or blackish (M) | |||
No images available yet | |||
FCF - (HY: July - December; SY January - March) | |||
Wings tinged with brown, contrasting with blue-gray back; primary coverts narrow, pointed, and with little or no edging; crown dark gray (F) or black (M) | |||
M |
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F |
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FCU - (SY: March - August) | |||
Wings tinged with brown, contrasting with blue-gray back; primary coverts narrow, pointed, and with little or no edging; crown dark gray (F) or black (M) | |||
No images available yet | |||
DCB - (AHY: July - December; ASY January - March) | |||
Wings and back uniformly blue-gray; primary coverts relatively broad, rounded, and with bluish edging; crown dark gray (F) or black (M) | |||
M |
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F |
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DCU - (ASY: March - August) | |||
Wings and back uniformly blue-gray; primary coverts relatively broad, rounded, and with bluish edging; crown dark gray (F) or black (M) | |||
No images available yet |
FPJ - (HY: June - August) | |
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Yellowish to whitish gape; some speckling on head and throat; some natal down feathers remaining | |
No images available yet | |
FPF - (HY: July - September) | |
Crown and lesser and sometimes median coverts being replaced | |
No images available yet | |
FPA - (SY: March - April) | |
Wings tinged with brown, contrasting with blue-gray back; primary coverts narrow, pointed, and with little or no edging; some body feathers in active replacement | |
No images available yet | |
SPB - (SY: June - September) | |
Flight feathers being replaced, with at least some retained juvenile primaries or primary coverts that are distinctly pale and worn | |
No images available yet | |
DPB - (AHY: June - September) | |
Flight feathers being replaced, with retained feathers either distinctly adult (relatively dark and only moderately worn) or intermediate | |
No images available yet | |
DPA - (ASY: March - April) | |
Wings and back uniformly blue-gray; primary coverts relatively broad, rounded, and with bluish edging; some body feathers in active replacement | |
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 | March - April | Undergoing prealternate molt, but cycle is not reliably distinguishable |
M-FCU / UCU (FCU, DCU) | AHY | March - August | In formative, basic, or alternate plumage (molt completed), but cycle and plumage are not reliably distinguishable |