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Number of species: 79

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Northern Shrike - Lanius excubitor

Northern Shrike has a partial preformative molt, and absent to partial prealternate molts that are difficult to detect. Age can generally be determined readily by plumage. Although males are on average somewhat darker than females, sex can be reliably determined only through brood patch / cloacal protuberance during the breeding season.

Northern and Loggerhead Shrikes are fairly similar in appearance; Northern Shrike can be separated by a pale base to the lower mandible, a distinct white supercilium contrasting with the black eyeline, and extensive although sometimes faint barring on the underparts.

Quick tips

  • Look for molt limits among median and greater coverts or between the greater and primary coverts - on FCF/FCU (HY/SY) birds there are retained juvenile feathers with buffy tips contrasting with replaced all-black feathers; on DCB/DCU (AHY/ASY) birds the median, greater, and primary coverts are uniformly black.
  • Check the contrast between dark and pale on p6 - on FCF/FCU (HY/SY) birds there is a gradual transition, while on DCB/DCU (AHY/ASY) birds there is a sharp distinction.
  • Consider the overall appearance - FCF/FCU (HY/SY) birds have a brownish tone initially, gradually becoming more grayish; DCB/DCU (AHY/ASY) birds are uniformly gray above and white below, aside from light barring on the breast.

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: June - October)
Brownish wash overall, with moderate to heavy barring on underparts
U
Thumbnail - MG2-1272-07897-Lanius_excubitor_AOU_7_52-3597.jpg Thumbnail - MG2-1272-07897-Lanius_excubitor_AOU_7_52-3595.jpg Thumbnail - MG2-1272-07897-Lanius_excubitor_AOU_7_52-3596.jpg
FCF - (HY: October - December; SY January - March)
Some to all greater coverts blackish, contrasting with the brownish-gray primary coverts and unreplaced greater coverts
U
Thumbnail - MG2-1222-70302-Lanius_excubitor_AOU_7_52-3591.jpg Thumbnail - MG2-1222-70302-Lanius_excubitor_AOU_7_52-3590.jpg
FCU - (SY: March - October)
Some to all greater coverts blackish, contrasting with the brownish-gray primary coverts and unreplaced greater coverts; sometimes molt limits among the secondaries or rectrices
No images available yet
DCB - (AHY: July - December; ASY January - March)
Greater coverts uniformly blackish, similar to or only slightly darker than the primary coverts; secondaries and rectrices uniform in colour and wear
U
Thumbnail - MG2-1342-01002-Lanius_excubitor_AOU_7_52-3603.jpg Thumbnail - MG2-1342-01002-Lanius_excubitor_AOU_7_52-3601.jpg Thumbnail - MG2-1342-01002-Lanius_excubitor_AOU_7_52-3602.jpg
DCU - (ASY: March - October)
Greater coverts uniformly blackish, similar to or only slightly darker than the primary coverts; secondaries and rectrices uniform in colour and wear
U
Thumbnail - MG2-1232-58510-Lanius_excubitor_AOU_7_52-3594.jpg Thumbnail - MG2-1232-58510-Lanius_excubitor_AOU_7_52-3592.jpg Thumbnail - MG2-1232-58510-Lanius_excubitor_AOU_7_52-3593.jpg

Individuals in active molt

FPJ - (HY: June - August)
Brownish wash overall, with moderate to heavy barring on underparts; some natal down remaining and/or juvenile flight feathers still growing in
No images available yet
FPF - (HY: October - December)
Similar to FCF, with some to all median and greater coverts and occasionally one to all tertials being replaced
No images available yet
FPA - (SY: March - April)
Similar to FCF, with some body feathers and up to two inner greater coverts, four inner secondaries, and two central rectrices being replaced
No images available yet
SPB - (SY: July - October)
Flight feathers being replaced, with retained juvenile primaries, secondaries, and/or primary coverts distinctly brownish
No images available yet
DPB - (AHY: July - October)
Flight feathers being replaced, with retained primaries, secondaries, and/or primary coverts either distinctly adult (blackish) or intermediate
No images available yet
DPA - (ASY: March - April)
Similar to FCF, with some 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 October - October Undergoing preformative or prebasic molt, but cycle is not reliably distinguishable
M-FCF / UCU (FCF, SCB, DCB) U/AHY October - March In formative or basic plumage (molt completed), but cycle is not reliably distinguishable
M-FPA / UPA (FPA, DPA) AHY March - April Undergoing prealternate molt, but cycle is not reliably distinguishable
M-FCU / UCU (FCU, DCU) AHY March - October In formative, basic, or alternate plumage (molt completed), but cycle and plumage are not reliably distinguishable

Number of species: 79

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