About Macronectes halli Mathews, 1912
This species, the northern giant petrel, has the scientific name Macronectes halli Mathews, 1912. The northern giant petrel averages 90 cm (35 in) in total length, with an overall length range of 80 to 95 cm (31 to 37 in). Its wingspan measures 150 to 210 cm (59 to 83 in). Body size is somewhat variable across individuals and colonies, and this species is broadly the same size as its close relative, the southern giant petrel. The colony with the largest-bodied individuals is located in the South Georgia Islands, where 56 adult males averaged 4.9 kg (11 lb) and 43 adult females averaged 3.72 kg (8.2 lb). The smallest-bodied individuals belong to the colony on the Chatham Islands, where 19 adult males averaged 3.66 kg (8.1 lb) and 21 adult females averaged 2.83 kg (6.2 lb). Overall, the total weight range for the species is 2.5 to 5.8 kg (5.5 to 12.8 lb). The adult's plumage has a grey-brown body, with lighter coloration on the forehead, sides of the face, and chin. Its bill is between 90 and 110 mm (3.5–4.3 in) long, and is slightly longer on average than the bill of the southern giant petrel. The bill is pinkish yellow with a brown tip. The northern giant petrel has grey eyes. On average, the tarsus of the northern giant petrel is slightly longer than that of the southern giant petrel, while the southern giant petrel has longer wings on average. Juvenile Macronectes halli are entirely dark brown, and their plumage lightens as they age. This species can be distinguished from the southern giant petrel (Macronectes giganteus) by bill color: the top of the bill is green on the southern species. The northern giant petrel is a pelagic seabird. It is found throughout the Southern Ocean north of the Antarctic Convergence Zone, and extends further north through the coastal waters of Chile, Argentina, South Africa, New Zealand, and half of Australia. Over 4,500 breeding pairs nest on islands within the South Georgia group. The species also nests on some of the Chatham Islands, Kerguelen Islands, Crozet Islands, Macquarie Island, and other additional islands. The overall total range of the northern giant petrel covers 82,600,000 km² (31,900,000 sq mi).
