National Geographic Magazine/Volume 31/Number 4/Friends of Our Forests/Blue-winged Warbler
The Warblers of North America
Range: Breeds from southeastern Minnesota, southern Michigan, western New York, Massachusetts (rarely), and southern Connecticut south to northeastern Kansas, central Missouri, Kentucky, Maryland, and Delaware; winters from southern Mexico (Puebla) to Guatemala.
Like the golden-wing, the blue-winged warbler is confined to the Eastern States, but it ranges considerably farther west than that species and occurs almost or quite to the Plains. The blue-wing is in many ways an inconspicuous member of the warbler group, but, because of its perplexing relationship with the golden-wing, Brewster's warbler, and Lawrence's warbler, its ornithological interest is excelled by few. Like the golden-wing, it prefers deciduous trees and second growths and shuns the deeper parts of the forests. It has the habit—shared by the golden-wing and chickadee—of hanging from the under side of any particular cluster it wishes to investigate, and no doubt it makes sure of insects that defy the less careful search of most other species. The ordinary song of the blue-wing is comparable to the golden-wing's, being in fact little else than an apology for a song, with the same insectlike quality. This warbler, though of distinctly arboreal habits, prefers to nest on the ground, or a few inches above it, in a tuft of grass, a clump of goldenrods, or at the foot of a sapling.
The nest is rather bulky, composed of leaves and grasses, put together after the artless manner of its kind; but it is usually well concealed by the surrounding screen of grass or weeds from any but chance discovery.