Macronectes halli averages 90 cm (35 in) in length, with a range of 80 to 95 cm (31 to 37 in), possessing a wingspan of 150 to 210 cm (59 to 83 in). Size is somewhat variable and this species is broadly the same size as its southern sister species. The largest-bodied colony is in the South Georgia Islands, where 56 males averaged 4.9 kg (11 lb) and 43 females average 3.72 kg (8.2 lb). The smallest-bodied are on the Chatham Islands, where 19 males averaged 3.66 kg (8.1 lb) and 21 females averaged 2.83 kg (6.2 lb). Overall, weight for the species can range from 2.5 to 5.8 kg (5.5 to 12.8 lb). Its plumage consists of grey-brown body with lighter coloured forehead, sides of face, and chin. Its bill is between 90 and 110 mm (3.5–4.3 in) long, slightly longer on average than the southern giant petrel, and is pinkish yellow with a brown tip. Its eyes are grey. The tarsus of the northern giant petrel is slightly longer on average than the southern species, but the southern has longer wings on average. The juvenile Macronectes halli is entirely dark brown and lightens as it ages. It can be differentiated from Macronectes giganteus by the top of the bill, which on the southern species is green. Northern giant petrels forage in similar locations to southern giant petrels, but at different times due to the earlier breeding season of northern giant petrels. It is thought this temporal segre...Learn more about Northern Giant Petrel