Pine Warbler - Setophaga pinus

Pine Warbler has a partial preformative molt but no prealternate molts. Plumage differs by age and sex, but only subtly, and for many individuals, age can be reliably confirmed only through skull ossification in fall, and sex through brood patch or cloacal protuberance during the breeding season.

Quick tips

• Examine the primary coverts, which on FCF (HY/SY) individuals are generally paler brown than the darker and fresher greater coverts, where as on DCB (AHY/ASY) birds there is less contrast between these feather tracts, although by spring the difference between age classes can be subtle.
• Check the shape of the outer rectrices - on FCF (HY/SY) birds they are fairly pointed and often abraded by spring, while on DCB (AHY/ASY) birds they are broader, fairly rounded, and more likely to remain fresh, but again there are many intermediates that are unhelpful for ageing.
• Consider the colour of the underparts - DCB (AHY/ASY) males have a yellowish to yellow breast contrasting with a white belly, FCF (HY/SY) males have a yellowish breast and whitish to white belly, DCB (AHY/ASY) females have a greenish-yellow breast and white to buff belly, and FCF (HY/SY) females show relatively little contrast between a dull yellowish breast and buff belly.

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