Blackpoll Warbler - Setophaga striata

Blackpoll Warbler has a partial preformative molt and partial prealternate molts that include some to all greater coverts and some to all tertials. Although plumage varies somewhat by age and sex, differences can be subtle, and the age of many individuals is reliably confirmed only through skull ossification in fall, and in spring many intermediates cannot be aged with certainty. Sex can generally be determined by plumage from FCA (SY) onward.

Quick tips

• Look at the primary coverts - they are relatively narrow and pointed on FCF/FCA (HY/SY) birds and can be visibly paler and more worn than the greater coverts, whereas on DCB/DCA (AHY/ASY) birds they tend to be broader and more rounded, and only moderately paler than the greater coverts.
• Examine the outer rectrices - they are usually somewhat paler and a bit narrower and more pointed on FCF/FCA (HY/SY) birds as compared to DCB/DCA (AHY/ASY), but the differences are relatively subtle in this species, and only the extremes may be helpful for ageing.
• In alternate plumage (spring/summer), examine the crown - it is solid black on DCA (ASY) males, black with light mottling on FCA (SY) males, olive-gray with distinct black streaks on DCA (ASY) females, and olive-gray with indistinct dark streaks on FCA (SY) females.
• In formative/basic plumage (fall/winter), consider the underparts - DCB (AHY) males have distinct black streaks on a white background, sometimes with a yellow tinge; DCB (AHY) females have moderately distinct dark streaks on a largely yellowish background; FCF (HY) birds have indistinct streaking on a variably yellowish-white background.

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