What is the giant southern petrel?
The wings are greyish-brown with yellow feathers on the leading edge. Their eyes are light grey to white. Both morphs have a large yellow-horned bill with a light green tip and grey-brown legs. The sexes are similar, although males are 20% heavier, with larger bills. Juveniles of the black morph are spiny black with a yellow bill, their plumage becoming lighter with age.
The southern giant petrel is the largest of all petrel species, reaching the size of a small albatross but with shorter, narrower wings, and a more humpbacked form. Two color morphs: the white morph (c.10%) and the black morph (c.90%). White morph birds are white, usually with black markings on their body and wings and dark brown eyes. Adult dark morph birds have a mainly dark grey-brown body with a head, neck, and upper breast.
Vocalization: Southern giant petrels make guttural rumbling and crying sounds during threats and courtship displays, raise their bills when threatened, and "click" their bills during mating. They make noise when feeding in flocks. Chicks make piping and quiet peeping sounds.
Similar species: The black-faced southern giant petrels are very similar to the northern giant petrels, with the color of the bill tip (reddish-brown in the northern, light green in the southern) being the only character that is reliable for all age groups, especially the black-faced juveniles. In the New Zealand area, adult northern giant petrels have yellow feathers limited to their faces, while adult southern giant petrels have yellow heads, necks, and upper breasts, contrasting with the rest of the dark feathers to create a two-toned appearance. Northern giant petrels elsewhere (i.e. the South Atlantic) may be lighter in colour from bill to undertail, but without the distinctly two-toned appearance of the adult black-faced southern giant petrels. Sooty and light-veined sooty albatrosses are slimmer and longer-tailed than giant petrels and have black bills.
Southern giant petrels are pelagic and circumpolar, generally found between subantarctic and Antarctic latitudes from 40°–68°S, breeding as far south as the continent of Antarctica. The closest breeding population in the New Zealand area is on subantarctic Macquarie Island, with 2,145 pairs of birds. Other island breeding sites (roughly from east to west) include Heard, Kerguelen, Crozet, Prince Edward, Marion, Go, Bouvetland, South Georgia, South Orkney, South Sandwich, South Shetland, Falkland, Diego Ramirez Islands and Noir Islands.
The marine ranges of the two giant petrel species overlap considerably. In summer, southern giant petrels range from the subantarctic to the open Antarctic seas. In winter to early spring, they range throughout the Southern Ocean from subtropical waters north to Brazil in the South Atlantic. Adults remain relatively close to the colonies during the breeding season. Birds tracked from Macquarie Island foraged on the sea ice edge off Antarctica.
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