A medium-sized (4 ½ -5 inches) wood warbler, the male Blue-winged Warbler is most easily identified by its olive-green back, yellow breast, yellow forehead, black eye-stripes, and gray-blue wings with white wing bars. Female Blue-winged Warblers are similar to males, but are somewhat duller overall with an olive-green cast on the head and back. This species occasionally hybridizes with the related Golden-winged Warbler (Vermivora chrysoptera), producing a dominant hybrid form (“Brewster’s Warbler,” which is pale below and olive green above with the Blue-winged Warbler’s black eye-stripes) and, more rarely, a recessive hybrid form (“Lawrence’s Warbler,” which is yellow below and olive-green above with the Golden-winged Warbler’s black facial markings). The Blue-winged Warbler breeds in portions of the eastern United States and southern Canada from Minnesota east to Massachusetts and from Ontario south to northern Alabama. In winter, this species migrates south to southern Mexico and Central America. This species has recently expanded its range northward into areas inhabited by Golden-winged Warblers, perhaps being partially responsible for the latter species’ recent declines. Blue-winged Warblers primarily breed in semi-open woodland habitats, particularly around forest edges, clearings, and places where ecological disturbance (forest fires, for example) has recently occurred. In winter, this species utilizes similar types of habitat in humid tropical forests. Blue-winged Warblers eat a variety of small invertebrates, primarily moths. In appropriate habitat, Blue-winged Warblers may be seen foraging for food on leaves and branches at middle heights in the canopy. Birdwatchers may also listen for this species’ song, a buzzing “beee-bzzz” dropping in pitch at the end. Blue-winged Warblers are primarily active during the day.
Fairly uncommon migrant in spring, through-out May, and in autumn from mid-August to early September. Rare breeder in cutover fields and forests, usually in the western part of this region from mid-May to early July. The male has the entire crown yellow; the female only the forehead.