Size: small to medium. Plumage; head often with moustacial streaks; wings long and pointed; tails medium to long. Other characters: necks short; eye large surrounded by a colourful ring of bare skin; bill short with a tooth on upper mandible; nostril round with a boney central tubercle; legs short; brood patches in both sexes.
- Brown, L.H., E.K. Urban & K. Newman (1982). The Birds of Africa, Volume I. Academic Press, London.