This slim wagtail has a narrow white supercilium and a broken eye ring. The upperparts are grey and a yellow vent contrasting with whitish underparts makes it distinctive. The species looks somewhat similar to the yellow wagtail but has the yellow on its underside restricted to the throat and vent.

Breeding males have a black throat. The species is widely distributed in UK. The species is always associated with running water when breeding, although they may use man-made structures near streams for the nest. Outside the breeding season, they may also be seen around lakes, coasts and other watery habitats.

They forage singly or in pairs on meadows or on shallow water marshes. They also use rocks in water and will often perch on trees. They have a clear sharp call note and the song consists of trills. These birds feed on a variety of aquatic invertebrates including adult flies, mayflies, beetles, crustacea and molluscs.