The sooty shearwater (Ardenna grisea) is a medium-large shearwater in the seabird family Procellariidae. In New Zealand, it is also known by its Māori name , and as muttonbird, like its relatives the wedge-tailed shearwater (A. pacificus) and the Australian short-tailed shearwater (A. tenuirostris). Taxonomy The sooty shearwater was formally described in 1789 by the German naturalist Johann Friedrich Gmelin under the binomial name Procellaria grisea. The shearwater had been briefly described in 1777 by James Cook in the account of his second voyage to the Pacific, and in 1785 the English ornithologist John Latham had described a museum specimen. The sooty shearwater is now placed in the genus Ardenna, that was introduced in 1853 by Ludwig Reichenbach. The genus name Ardenna was used to refer to a seabird by Italian naturalist Ulisse Aldrovandi in 1603, and the specific epithet grisea is medieval Latin for "grey". The species is considered to be monotypic; no subspecies are recognised. It appears to be particularly closely related to the great shearwater (A. gravis) and the short-tailed shearwater, all blunt-tailed, black-billed species, but its precise relationships are obscure. In any case, these three species are among the larger species of shearwaters that have been moved into a separate genus Ardenna based on a phylogenetic analysis of mitochondrial DNA. Description Sooty shearwaters are in length with a wingspan. It has the typical "shearing" flight of the genus, dipping from side to side on stiff wings with few wing beats, the wingtips almost touching the water. Its flight is powerful and direct, with wings held stiff and straight, giving the impression of a very small albatross. This shearwater is identifiable by its dark plumage, which is responsible for its name. In poor viewing conditions, it looks all black, but in good light, it shows as dark chocolate-brown with a silvery strip along the center of the underwing. Usually loud, sooty shearwaters coo and croak while on the breeding grounds. In the Atlantic, it is the only such bird, whereas in the Pacific part of its range, other all-dark large shearwaters are found. The short-tailed shearwater in particular is almost impossible to tell apart from the present species at a distance. Distribution and habitat Sooty shearwaters breed on small islands in the south Pacific and south Atlantic Oceans, mainly around New Zealand, the Falkland Islands, Tierra del Fuego, and in the Auckland Islands and Phillip Island off