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Number of species: 41

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Eastern Kingbird - Tyrannus tyrannus

Eastern Kingbird has an incomplete to complete preformative molt that occurs primarily on the winter grounds, and partial prealternate molts. Sex in FCF (SY) and older individuals is reliably indicated by the shape of the outer primary.

Quick tips

  • Check the shape of the outermost primary - on FCJ (HY) birds it is rounded, while on FCF (SY) and older birds it is either tapered (females) or sharply pointed (males).
  • Examine the central flight feathers (innermost primaries and outermost secondaries) for any retained juvenile feathers that are contrastingly paler and more worn than adjacent feathers, which is indicative of FCF (SY) through at least the end of fall migration; all other non-juveniles on the breeding grounds should be considered M-FCF (AHY).
  • Examine the crown - FCJ (HY) individuals lack red feathers, while M-FCF (AHY) birds have a small central patch of red feathers, although it may be concealed.

Species account prepared by McGill Bird Observatory (2018). Last updated by Marcel Gahbauer (Mar 2022)

The molt categories displayed below may be filtered by month.

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Individuals not in molt

FCJ - (HY: June - October)
Upperparts lightly mottled with brownish tips on some feathers; crown uniformly dark gray; outermost primary rounded; plumage retained until after fall migration
U
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M-FCF - (U: October - December; AHY January - March)
Upperparts uniformly dark gray; concealed orange to red crown patch; outermost primary tapered (F) or pointed (M)
No images available yet
M-FCA - (AHY: April - October)
Upperparts uniformly dark gray; concealed orange to red crown patch; outermost primary tapered (F) or pointed (M)
M
Thumbnail - MG2-2201-54816-Tyrannus_tyrannus_AOU_7_52-3586.jpg Thumbnail - MG2-2201-54816-Tyrannus_tyrannus_AOU_7_52-3584.jpg Thumbnail - MG2-2201-54816-Tyrannus_tyrannus_AOU_7_52-3585.jpg
F
Thumbnail - MG2-2431-74212-Tyrannus_tyrannus_AOU_7_52-3589.jpg Thumbnail - MG2-2431-74212-Tyrannus_tyrannus_AOU_7_52-3587.jpg Thumbnail - MG2-2431-74212-Tyrannus_tyrannus_AOU_7_52-3588.jpg
FCF - (HY: October - December; SY January - March)
Innermost one or two primaries and/or up to two secondaries contrastingly pale and worn compared to other flight feathers; outermost primary tapered (F) or pointed (M); note that this class can only occasionally be recognized, and most are M-FCF
No images available yet
FCA - (SY: April - October)
Innermost one or two primaries and/or up to two secondaries contrastingly pale and worn compared to other flight feathers; outermost primary tapered (F) or pointed (M); note that this class can only occasionally be recognized, and most are M-FCA
No images available yet

Individuals in active molt

FPJ - (HY: June - July)
Similar to FCJ; some natal down remaining and/or juvenile flight feathers still growing in
No images available yet
FPF - (HY: September - December; SY January - March)
Almost all feather tracts being replaced, although the innermost one or two primaries and up to two secondaries may occasionally be retained
No images available yet
M-FPA - (AHY: March - May)
Similar to M-FCA, with up to four inner greater coverts and some to all tertials being replaced
No images available yet
M-SPB
Description to be developed.
No images available yet
SPB - (SY: September - December; TY January - February)
Flight feathers being replaced, with retained juvenile inner primaries or secondaries distinctly pale and worn
No images available yet

Applicable unknown plumage/age classes

Molt classes Age Months Key traits
M-SPB / UPU (SPB, DPB) AHY September - February Undergoing prebasic molt, but cycle is not reliably distinguishable