Orange-crowned Warbler - Oreothlypis celata

Orange-crowned Warbler has a partial preformative molt that generally occurs before migration, and an absent to limited prealternate molt of feathers on the head and chin that is often difficult to detect. Plumage differences by age and sex are quite subtle in Orange-crowned Warbler; multiple criteria should be in agreement to determine age and sex, and some intermediates are better left as unknown; skulling to confirm age in fall is particularly important.

Especially in areas where two or more of the four recognized subspecies overlap during migration, variability among them can complicate ageing and sexing.

Quick tips

• Look at the tail - on FCF/FCU (HY/SY) birds the rectrices tend to be fairly narrow and pointed, and on DCB/DCU (AHY/ASY) birds they are relatively broad and rounded at the tip - but note that some individuals are intermediate in appearance and should be aged only in combination with other characteristics.
• Examine the concealed crown patch - it may be minimal or absent on FCF/FCU (HY/SY) birds, though beware that on some FCU (SY) males it can be quite large, while on DCB/DCU (AHY/ASY) birds it is always at least moderately large (9 mm or greater in length).
• Look at the primary coverts - on FCF/FCU (HY/SY) birds they tend to be narrow with little or no edging and generally somewhat duller or paler than the greater coverts; on DCB/DCU (AHY/ASY) birds they are relatively broad and may have olive edging and are uniform in appearance with the greater coverts - but as with the rectrices, there is considerable variability in shape and colour and intermediates are common in which the primary coverts are not a distinct indicator of age.
• Consider wing chord to verify sex, as short or long extremes can be useful (measurements cited from Pyle 1997): V.c. celata:  female only (54-56 mm), overlap (57-62 mm), male only (63-65 mm) V.c. lutescens:  female only (51-54 mm), overlap (55-59 mm), male only (60-62 mm) V.c. orestera:  female only (55-57 mm), overlap (58-64 mm), male only (65-66 mm) V.c. sordida:  female only (54-56 mm), overlap (57-60 mm), male only (61-63 mm).

Species account prepared by McGill Bird Observatory (2016). Last updated by Marcel Gahbauer (Mar 2022)