5-6" (13-15 cm). Breeding male dull bluish above, streaked with black; breast and flanks blackish. Rump, crown, and small area at sides of breast yellow. Western male ("Audubon's Warbler") has yellow throat, large white patch in folded wing. Eastern male ("Myrtle Warbler") has white throat, 2 white wing bars. Females, fall males, and young are streaked gray-brown but always have yellow rump and white spots in tail.
