Black-and-white Warbler - Mniotilta varia

Black-and-white Warbler has a partial preformative molt and partial prealternate molts that usually include some to all tertials and occasionally one or both central rectrices. Sex and age can usually be determined reliably throughout the year.

Quick tips

• Examine the shape of the rectrices - on DCB/DCA (AHY/ASY) birds they tend to be broad and rounded while on FCF/FCA (HY/SY) birds they average more narrow and pointed, but note that the extent of white on the rectrices does not vary enough to be helpful except in extreme cases.
• Look at the primary coverts - on FCF/FCA (HY/SY) birds they are grayish (fall) to brownish (spring) and contrast moderately to strongly with the blackish greater coverts, but beware that even on DCB/DCA (AHY/ASY) birds the primary coverts are somewhat paler than the greater coverts.
• Consider the overall plumage - males are entirely black and white, while females are a slightly paler dusky-black and their flanks often have a buffy tinge.
• Look at the throat - only males have black markings, and in fall, only DCB (AHY) males have more than a trace of black in the throat.

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