Black-and-white Warblers are medium-sized warblers (small songbirds). They have a fairly long, slightly downcurved bill. The head often appears somewhat flat and streamlined, with a short neck. The wings are long and the tail is short. They measure 11 to 13 centimeters in length, with a wingspan of 18 to 22 centimeters. These birds are boldly striped in black and white. Their black wings are highlighted by two wide, white wing bars. Adult males have more obvious black streaking, particularly on the underparts and the cheek. Females (especially immatures) are paler, with less streaking and usually a wash of buff on the flanks. The undertail coverts have distinctive large black spots. Black-and-white Warblers act more like nuthatches than warblers, foraging for hidden insects in the bark of trees by creeping up, down, and around branches and trunks. Despite their arboreal foraging habits, they nest on the ground at the bases of trees. Deciduous forest and mixed forest are the preferred summer habitats of Black-and-white Warblers, usually with trees of mixed ages that provide a variety of foraging substrates. On migration, look for them in any forest or woodlot. They winter in forests and forest edges from Florida to Colombia. This species is of low conservation concern.
- The Black-and-white Warbler is the only member of the genus Mniotilta. The genus name means “moss-plucking,” a reference to its habit of probing bark and moss for insects.
- Black-and-white Warblers have an extra-long hind claw and heavier legs than other wood-warblers, which help them hold onto and move around on bark.
- The oldest known Black-and-white Warbler lived to be 11 years, 3 months old.