The white-breasted waterhen is a large and distinctive rail species with dark grey upperparts and flanks, and conspicuous white underparts, from which the species gains its common name. The face is also white, and the rear flanks and underside of the tail are reddish-brown. The beak is yellowish, with a reddish base, but becomes more olive outside of the breeding season (2) (3) (4) (5). The long legs are yellowish, with large, rather ungainly-looking feet (3) (4) (5), and the legs are dangled in flight (3). The female white-breasted waterhen is generally smaller than the male, with a somewhat duller beak, while juveniles have duller plumage, with the white of the underparts tinged brown, and a darker beak and legs (2) (5). This species is described as being very noisy during the breeding season, producing a loud call consisting of various grunts, roars, quacks and chuckles, followed by a repeated kru-ak, kru-ak, kru-ak-a-wak-wak that may continue for 15 minutes or more (2) (3 (4) (5). It also produces a sharp, metallic pwik call (4) (5).
Three subspecies of white-breasted waterhen are generally recognised: Amaurornis phoenicurus phoenicurus, Amaurornis phoenicurus insularis and Amaurornis phoenicurus leucomelana (6), with some also recognising a fourth, Amaurornis phoenicurus midnicobaricus (2). The subspecies are separated mainly by the extent of grey on the head and flanks (2) (5), and by the colour of the underparts, which are more olive in A. p. midnicobaricus (2). However, there is considerable variation between individuals, and some populations show intermediate head patterns (2).
- Length: 28 - 33 cm (2)
- Male weight: 203 - 328 g (2)
- Female weight: 166 - 225 g (2)