High Quality Content by WIKIPEDIA articles! The Bachman`s Warbler, Vermivora bachmanii, is (or was) a small passerine bird that inhabits the swamps and lowland forests of the southeast United States. This warbler is a migrant, wintering in Cuba. The Bachman’s Warbler is small for a warbler and is unique for its thin and decurved bill. It has strong sexual dimorphism. Adult males are olive above and yellow below, with a black upper chest and forecrown giving them a distinctive look. Adult females have an olive-green back and a gray crown, while the underbelly is a light yellow. Immatures are a dull gray.