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Number of species: 41

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Canada Warbler - Cardellina canadensis

Canada Warbler has a partial preformative molt, and limited to partial prealternate molts that are restricted primarily to body feathers but can include up to three inner greater coverts in the first cycle. Sexes can overlap in appearance during the first cycle; especially by spring age determination can be challenging as differences in key characteristics are often subtle, and therefore some intermediates are best considered as M-FCU (AHY).

Quick tips

  • Look for molt limits on the wing - on DCB/DCU (AHY/ASY) birds the wing is uniformly gray, while on FCF/FCU (HY/SY) birds there is often a visible contrast between the gray greater coverts and brownish-gray primary coverts, primaries, and secondaries.
  • Examine the forehead - it is moderately to extensively black on all DCB/DCU (AHY/ASY) males and FCU (SY) males, and has black flecks on some DCU (ASY) females and FCF (HY) males, but is greenish-gray and lacking black on other DCU (ASY) females and FCF (HY) males and all FCF/FCU (HY/SY) females.
  • Consider the rectrices - on FCF/FCU (HY/SY) birds they are relatively narrow and pointed, while on DCB/DCU (AHY/ASY) birds they tend to be broader and more rounded, but there is considerable variation, and only extremes may be useful in helping with ageing.

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 - July)
Brownish above and dull below; buffy wing bars
No images available yet
FCF - (HY: June - December; SY January - April)
Primary coverts somewhat brownish, contrasting with grayish greater coverts; rectrices usually narrow and somewhat pointed; forehead greenish-gray, without (F) or sometimes with (M) a few blackish flecks; necklace faint (F) or dark and distinct but finely marked (M)
M
Thumbnail - MG2-2600-16288-Cardellina_canadensis_AOU_7_52-2332.jpg Thumbnail - MG2-2600-16288-Cardellina_canadensis_AOU_7_52-2334.jpg Thumbnail - MG2-2600-16288-Cardellina_canadensis_AOU_7_52-2333.jpg
F
Thumbnail - MG2-1840-76968-Cardellina_canadensis_AOU_7_52-2338.jpg Thumbnail - MG2-1840-76968-Cardellina_canadensis_AOU_7_52-2340.jpg Thumbnail - MG2-1840-76968-Cardellina_canadensis_AOU_7_52-2339.jpg
FCU - (SY: February - August)
Primary coverts, primaries, and secondaries brownish, contrasting with grayish greater coverts; rectrices usually narrow and somewhat pointed; forehead greenish-gray (F) or blackish (M); necklace olive (F) or blackish (M)
M
Thumbnail - MH3-2500-65385-Cardellina_canadensis_AOU_7_52-332.jpg Thumbnail - MH3-2500-65385-Cardellina_canadensis_AOU_7_52-333.jpg Thumbnail - MH3-2500-65385-Cardellina_canadensis_AOU_7_52-334.jpg
F
Thumbnail - MG2-2650-43180-Cardellina_canadensis_AOU_7_52-2323.jpg Thumbnail - MG2-2650-43180-Cardellina_canadensis_AOU_7_52-2325.jpg Thumbnail - MG2-2650-43180-Cardellina_canadensis_AOU_7_52-2324.jpg
DCB - (AHY: June - December; ASY January - April)
Primary coverts and greater coverts similarly gray; rectrices usually somewhat broad and rounded; forehead grayish (F) or bluish with black flecks (M); necklace olive-gray (F) or black and boldly marked (M)
M
Thumbnail - MG2-1840-76984-Cardellina_canadensis_AOU_7_52-2326.jpg Thumbnail - MG2-1840-76984-Cardellina_canadensis_AOU_7_52-2328.jpg Thumbnail - MG2-1840-76984-Cardellina_canadensis_AOU_7_52-2327.jpg
F
Thumbnail - MG2-2600-16327-Cardellina_canadensis_AOU_7_52-2329.jpg Thumbnail - MG2-2600-16327-Cardellina_canadensis_AOU_7_52-2331.jpg Thumbnail - MG2-2600-16327-Cardellina_canadensis_AOU_7_52-2330.jpg
DCU - (ASY: February - August)
Primary coverts and greater coverts similarly gray; rectrices usually somewhat broad and rounded; forehead grayish with some black flecks (F) or bluish with black flecks (M); necklace olive-gray (F) or black and boldly marked (M)
M
Thumbnail - MG2-2490-24749-Cardellina_canadensis_AOU_7_52-2314.jpg Thumbnail - MG2-2490-24749-Cardellina_canadensis_AOU_7_52-2316.jpg Thumbnail - MG2-2490-24749-Cardellina_canadensis_AOU_7_52-2315.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 being replaced
No images available yet
FPA - (SY: January - May)
Similar to FCU; head and body feathers being replaced, and occasionally up to three inner greater coverts as well
No images available yet
SPB - (SY: June - August)
Flight feathers being replaced, with retained juvenile primaries, secondaries, and/or primary coverts distinctly pale brownish 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 (generally grayish, less worn) or intermediate
No images available yet
DPA - (ASY: January - May)
Similar to DCB; some head and body 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 - May Undergoing prealternate molt, but cycle is not reliably distinguishable
M-FCU / UCU (FCU, DCU) AHY February - August In formative, basic, or alternate plumage (molt completed), but cycle and plumage are not reliably distinguishable