Large black-and-white wagtail with an intricately and uniquely striped head pattern. Wings and outer tail feathers flash brightly in flight. Adult male is black-backed, while the female and immature have a duller gray-brown back. Simple song is a compilation of a few high phrases of whistles and twitters. Call is harsh and buzzy. Like other wagtails, often found near water, but tends to be more specific in its requirements than some of its relatives; favors fast-flowing lowland rivers with vegetation-lined banks, islands, and gravel banks.