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Number of species: 79

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Brown Thrasher - Toxostoma rufum

Brown Thrasher has a partial preformative molt but no prealternate molts. Age can often be determined by examination of the wing and tail, although by spring characteristics can become less distinct, and some individuals may need to be considered M-FCU (AHY). Sex can be reliably determined only by brood patch / cloacal protuberance during the breeding season.

Quick tips

  • Carefully examine the greater coverts - on FCF (HY/SY) birds, some to many of the innermost ones are contrastingly long, fresh, and dark, whereas on DCB (AHY/ASY) individuals they are uniformly fresh, though beware a pseudolimit with the outermost greater coverts having somewhat rustier tips.
  • In fall, check the iris - on FCF (HY) birds it is grayish to pale yellow, while on DCB (AHY) birds it is yellowish-orange to orange.
  • Examine the tail - on FCF (HY/SY) birds the outer feathers are somewhat more tapered and worn, especially by spring; on DCB (AHY/ASY) birds they are relatively broad, rounded, and tend to show less wear.

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: May - August)
Dull brown above with some pale mottling; iris grayish
No images available yet
FCF - (HY/SY: July - following August)
Rectrices relatively narrow, and fairly worn by spring; iris grayish to pale yellow; outer greater coverts shorter and duller than replaced inner feathers
U
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DCB - (AHY/ASY: July - following August)
Rectrices relatively broad; iris yellowish-orange to orange; greater coverts uniform in length and wear, but beware a cline toward darker inner feathers
U
Thumbnail - MG2-1232-26380-Toxostoma_rufum_AOU_7_52-3086.jpg Thumbnail - MG2-1232-26380-Toxostoma_rufum_AOU_7_52-3084.jpg Thumbnail - MG2-1232-26380-Toxostoma_rufum_AOU_7_52-3085.jpg

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Individuals in active molt

FPJ - (HY: May - July)
Similar to FCJ; some natal down remaining and/or juvenile flight feathers still growing in
No images available yet
FPF - (HY: July - September)
Similar to FCF; body feathers and some to most greater coverts and some to all tertials being replaced
U
Thumbnail - MG2-0972-31256-Toxostoma_rufum_AOU_7_52-3110.jpg Thumbnail - MG2-0972-31256-Toxostoma_rufum_AOU_7_52-3108.jpg Thumbnail - MG2-0972-31256-Toxostoma_rufum_AOU_7_52-3109.jpg
SPB - (SY: July - August)
Flight feathers being replaced, with retained juvenile primaries, secondaries, and/or primary coverts distinctly pale and worn
No images available yet
DPB - (AHY: July - August)
Flight feathers being replaced, with retained primaries, secondaries, and/or primary coverts either distinctly adult (relatively dark brown and not overly worn) or intermediate
No images available yet

Applicable unknown plumage/age classes

Molt classes Age Months Key traits
M-FPF / UPU (FPF, SPB, DPB) U July - August 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: 79

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