This unique flightless bird is roughly the size of a hen, making it the world's largest rail. It has a stocky body with stout red legs, and is brightly coloured with a large robust red bill and attractive green and blue plumage (4). It has small wings (4), which are used in courtship and aggressive displays (5). The call is a slow and deep 'coo-eet' and the alarm call is a deep 'oomf' (3). Chicks have black down and a black beak (5).