Nondescript warbler, generally olive-colored overall, but different populations vary from grayer to brighter yellow. Overall very plain and unmarked, but note short darkish line through eye and thin pale eye arcs. Forages for insects in scrubby areas, woodland edge, and thickets. Namesake orange crown is very difficult to see, and usually only a faint wash at best. More common in western North America, from Alaska to Mexico, where populations are brighter yellow-green. Birds in eastern North America are scarcer and drabber, often with a more contrasting grayish head. Bright yellow undertail coverts help separate Orange-crowned from the similarly drab Tennessee Warbler.