12 cm (5") Locally common in eastern United States; rare in southern Ontario. Found in old pastures overgrown with saplings, thickets along streams and swamps.
Mostly yellow with blue-gray wings with two white wing bars. White or yellow undertail coverts. Long slender bill. Black line through eye.
Hybridizes with Golden-winged Warbler to produce Brewster's and Lawrence's warblers.
Nests on ground.
Song: buzzy.