Fairly common bird in secondary growth and field edges, particularly along power lines. Expanding n. and kicking GWWA out or hybridizing. An unusual song, a loud insect-like ‘fuzzzz buzzzzzz.’ Stays lower than many warblers and often hangs upside down chickadee-like. A somewhat sleek bird with average proportions. Always look for the striking black eyeline, pointed at rear and bordered by yellow. Its black bill is so pointed it looks dangerous, typical of Vermivora. Bright yellow underparts all the way to the white vent. Flicks tail open showing white outer tail feathers. Green-backed with 2 wing bars, grayer wings and tail. Ad ♂: extensive yellow forehead and broad white wing bars. Ad ♀/imm ♂: limited yellow on forehead. Imm ♀: green forehead with yellow supercilium. Wing bars typically yellow (this is not a sign of hybridization).