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Number of species: 82

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Blue Jay - Cyanocitta cristata

Blue Jay has a partial preformative molt and no prealternate molts. Determination of sex is limited to brood patch / cloacal protuberance during the breeding season.

Quick tips

  • Look at the alula and primary coverts - on FCF (HY/SY) birds they are grayish-brown and unbarred, while on DCB (AHY/ASY) birds they are blue with dark bars.
  • Check for molt limits among the greater coverts - FCF (HY/SY) birds often retain dull grayish blue outer coverts contrasting with brighter blue inner coverts, while on DCB (AHY/ASY) birds all greater coverts are bright blue with dark barring.
  • Examine the tail - some FCF (HY/SY) individuals have replaced their central rectrices, which are contrastingly fresh and bright.
  • Examine the upper mandible lining - on FCF (HY/SY) birds it is a mottled mix of white and black, while on DCB (AHY/ASY) birds it is mostly to entirely black.

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

Individuals not in molt

FCJ - (HY: May - August)
Similar to FCF, but with more grayish on the face, back, and wings
No images available yet
FCF - (HY/SY: June - following August)
Primary coverts and alula grayish and lacking bars; upper mandible lining whitish to mottled black and white; outer greater coverts duller than replaced inner greater coverts on some individuals; central rectrices sometimes contrastingly bright blue
U
Thumbnail - MG2-1212-69278-Cyanocitta_cristata_AOU_7_52-3666.jpg Thumbnail - MG2-1212-69278-Cyanocitta_cristata_AOU_7_52-3664.jpg Thumbnail - MG2-1212-69278-Cyanocitta_cristata_AOU_7_52-3665.jpg

Thumbnail - MG2-1383-62365-Cyanocitta_cristata_AOU_7_52-3678.jpg Thumbnail - MG2-1383-62365-Cyanocitta_cristata_AOU_7_52-3676.jpg Thumbnail - MG2-1383-62365-Cyanocitta_cristata_AOU_7_52-3677.jpg
DCB - (AHY/ASY: June - following August)
Primary coverts and alula blue with dark barring; upper mandible lining mostly to entirely black; greater coverts uniformly bright blue with distinct white tips; central rectrices not contrasting substantially with others
U
Thumbnail - MG2-1383-62339-Cyanocitta_cristata_AOU_7_52-3672.jpg Thumbnail - MG2-1383-62339-Cyanocitta_cristata_AOU_7_52-3670.jpg Thumbnail - MG2-1383-62339-Cyanocitta_cristata_AOU_7_52-3671.jpg

Individuals in active molt

FPJ - (HY: May - July)
Similar to FCF, but with more grayish on the face, back, and wings; some natal down remaining and/or juvenile flight feathers still growing in
No images available yet
FPF - (HY: June - October)
Similar to FCF, with some to all greater coverts and tertials being replaced, and sometimes also the central rectrices
No images available yet
SPB - (SY: June - September)
Flight feathers being replaced, with retained juvenile primaries, secondaries, and/or primary coverts distinctly dull and very worn
No images available yet
DPB - (AHY: June - September)
Flight feathers being replaced, with retained primaries, secondaries, and/or primary coverts either distinctly adult (bluish, with moderate wear) or intermediate
No images available yet

Applicable unknown plumage/age classes

Molt classes Age Months Key traits
M-FPF / UPU (FPF, SPB, DPB) U June - September 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: 82

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