A blackish brown bird with a white throat and a white strip down the center of the breast and belly. Upperparts are blackish with white flanks and a white trailing edge to the secondaries (the inner part of the wing).
Nests in natural crevices on rocky cliffs or canyon walls, from sea level to high mountain peaks. Forages over virtually any terrestrial habitat that features small aerial insects. Sometimes nests in buildings, bridges, and overpasses, sometimes in cities.
Ornithologists recognize two very similar subspecies: saxatalis of North America and the darker nigrior of Central America.