Its plumage was white, sometimes with a few blue mottles, and it was probably flightless, like its other close relative the Takahe.
Similar, entirely blue birds were also described, but it is not clear if they belong to this species or are simply Purple Swamphens (which can also be found on the island). The feathers on the two extant skins are white.
This bird was first described by John White in his Journal of a Voyage to New South Wales (1790), which also contained an illustration.
It was a resident of Lord Howe Island, Australia. It was not uncommon when the bird was first described, but was soon hunted to extinction by whalers and sailors.
There are two skins of the bird in existence, in the museums of Liverpool and Vienna. There are also several paintings, and some subfossil bones.