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Number of species: 41

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Blue-winged Warbler - Vermivora cyanoptera

Blue-winged Warbler has a partial preformative molt; prealternate molts are generally absent or at most limited to head feathers. Both age and sex can usually be easily determined by plumage throughout the year.

Blue-winged Warbler frequently hybridizes with Golden-winged Warbler; the appearance of hybrids can be somewhat variable, but the general principles of ageing and sexing can usually be applied.

Quick tips

  • Examine the primary coverts - on DCB/DCU (AHY/ASY) individuals they are dark gray with pale edging, while on FCF/FCU (HY/SY) birds they are brownish and without edging.
  • Look at the crown and nape - on DCB/DCU (AHY/ASY) males the bright yellow crown contrasts sharply with the greenish nape, on FCF/FCU (HY/SY) males and DCB/DCU (AHY/ASY) females the yellow crown fades in to the greenish nape, and on FCF/FCU (HY/SY) females the greenish-yellow crown shows little contrast with the nape.
  • Consider the eye line - on DCB/DCU (AHY/ASY) males it is bold black, on FCF/FCU (HY/SY) males and DCB/DCU (AHY/ASY) females it is blackish, and on FCF/FCU (HY/SY) females it is dark gray.
  • Examine the rectrices - on FCF/FCU (HY/SY) birds they are relatively narrow and tapered to a point with relatively small white patches on the outer feathers, while on DCB/DCU (AHY/ASY) birds they are more broad and rounded toward the tip, with larger white patches.

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: June - August)
Upperparts tinged olive; yellowish wing bars; eye line indistinct
No images available yet
FCF - (HY: June - December; SY January - April)
Primary coverts brownish gray with little or no edging; rectrices narrow and pointed; crown greenish yellow similar to nape (F) or contrastingly yellowish (M); eye line dark gray (F) to blackish (M)
F
Thumbnail - MG2-2330-10967-Vermivora_cyanoptera_AOU_7_52-2311.jpg Thumbnail - MG2-2330-10967-Vermivora_cyanoptera_AOU_7_52-2313.jpg Thumbnail - MG2-2330-10967-Vermivora_cyanoptera_AOU_7_52-2312.jpg
FCU - (SY: January - August)
Primary coverts brownish gray with little or no edging; rectrices narrow and pointed; crown greenish yellow similar to nape (F) or contrastingly yellowish (M); eye line dark gray (F) to blackish (M)
M
Thumbnail - MH3-2530-54702-Vermivora_cyanoptera_AOU_7_52-323.jpg Thumbnail - MH3-2530-54702-Vermivora_cyanoptera_AOU_7_52-324.jpg Thumbnail - MH3-2530-54702-Vermivora_cyanoptera_AOU_7_52-325.jpg
DCB - (AHY: June - December; ASY January - April)
Primary coverts dark gray with pale edging; rectrices somewhat broad and rounded; crown yellow (F) to bright yellow (M); eye line blackish (F) to black (M)
No images available yet
DCU - (ASY: January - August)
Primary coverts dark gray with pale edging; rectrices somewhat broad and rounded; crown yellow (F) to bright yellow (M); eye line blackish (F) to black (M)
M
Thumbnail - MG2-2550-58412-Vermivora_cyanoptera_AOU_7_52-2308.jpg Thumbnail - MG2-2550-58412-Vermivora_cyanoptera_AOU_7_52-2310.jpg Thumbnail - MG2-2550-58412-Vermivora_cyanoptera_AOU_7_52-2309.jpg

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: June - August)
Similar to FCF; median and greater coverts and sometimes the greater alula being replaced
No images available yet
FPA - (SY: January - April)
Similar to FCF; some head feathers being replaced
No images available yet
SPB - (SY: June - August)
Flight feathers being replaced, with retained juvenile primaries, secondaries, and/or primary coverts distinctly pale brown and very worn
No images available yet
DPB - (AHY: June - August)
Flight feathers being replaced, with retained primaries, secondaries, and/or primary coverts either distinctly adult (relatively gray, less worn) or intermediate
No images available yet
DPA - (ASY: January - April)
Similar to DCB; some head feathers being replaced
No images available yet

Applicable unknown plumage/age classes

Molt classes Age Months Key traits
M-FPF / UPU (FPF, SPB, DPB) U June - August Undergoing preformative or prebasic molt, but cycle is not reliably distinguishable
M-FCF / UCU (FCF, SCB, DCB) U/AHY June - April In formative or basic plumage (molt completed), but cycle is not reliably distinguishable
M-FPA / UPA (FPA, DPA) AHY January - April Undergoing prealternate molt, but cycle is not reliably distinguishable
M-FCA / UCA (FCA, DCA) AHY January - August In alternate plumage (molt completed), but cycle is not reliably distinguishable