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Number of species: 85

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House Finch - Haemorhous mexicanus

House Finch has a variable preformative molt that can range from partial to complete, but is most frequently incomplete, including all greater coverts, some to all tertials, sometimes additional secondaries, usually at least some rectrices, and occasionally also some outer primaries and primary coverts. Prealternate molts are believed to be generally absent. Post-juvenile House Finches can usually be sexed easily by presence (male) or absence (female) of red plumage.

Because of the potential for a complete preformative molt, House Finches with uniform plumage are most reliably aged by skull until late September, and in areas where complete preformative molts occur, such individuals should subsequently be considered M-FCF (U/AHY).

Quick tips

  • Look at the head and upper breast - any red plumage indicates a male, while lack of red generally suggests a female, although note that FCJ (juvenile) males also lack red until their preformative molt.
  • Compare the greater coverts and primary coverts - there is usually a molt limit between darker grayish-brown greater coverts and paler brown primary coverts on FCF (HY/SY) birds, while they appear largely uniform in colour and wear on DCB (AHY/ASY) birds.
  • Examine the primaries - some FCF (HY/SY) individuals show an eccentric molt, with darker/fresher outer primaries and inner secondaries; uniform primaries are less informative as they can occur at any age.
  • Check the rectrices - if some or all are narrow and tapered they indicate a FCF (HY/SY) bird, but if they are all uniformly broad and rounded the bird may be either FCF (HY/SY) or DCB (AHY/ASY).

Species account prepared by McGill Bird Observatory (2016). Last updated by Marcel Gahbauer (Mar 2022)

The molt categories displayed below may be filtered by month.

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Click on any image below to bring up the side-by-side comparison tool.

Individuals not in molt

FCJ - (HY: April - October)
Brownish overall and heavily streaked below; fairly distinct buff wing bars
U
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M-FCF - (U/AHY: June - following September)
Rectrices uniformly broad and rounded; primary coverts relatively broad and rounded and not contrasting strongly with greater coverts; primaries and secondaries uniform in wear; entirely brown and white (F) or moderately to heavily washed with red (occasionally orange) especially on head and upper breast (M); in some populations where preformative molt is incomplete, M-FCF can safely be considered DCB
M
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F
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FCF - (HY/SY: July - following September)
Appearance can vary considerably depending on extent of preformative molt; rectrices sometimes narrow and pointed or mixed with fresher, broader, and more rounded feathers (or sometimes uniformly broad and rounded); inner primary coverts usually contrastingly pale in comparison to fresher greater coverts; outer primaries and inner secondaries sometimes contrastingly fresh and with darker shafts than retained central block of feathers; entirely brown and white (F) or with some to moderate reddish wash, especially on head and upper breast (M)
M
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U
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Individuals in active molt

FPJ - (HY: April - September)
Similar to FCJ; some natal down remaining and/or juvenile flight feathers still growing in
No images available yet
FPF - (HY: July - October)
At minimum, all median and greater coverts and some to all tertials being replaced; often also some to all rectrices and some inner secondaries and outer primaries; occasionally even some outer primary coverts, and in rare cases all flight feathers
No images available yet
M-SPB
Description to be developed.
No images available yet
SPB - (SY: June - October)
Flight feathers being replaced, with retained juvenile primaries, secondaries, and/or primary coverts distinctly pale brown and very worn
No images available yet

Applicable unknown plumage/age classes

Molt classes Age Months Key traits
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

Number of species: 85

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