The Northern giant petrel, scientific name Macronectes halli in the north, also known as Hall's giant petrel, is a large hunting marine bird in the Southern Ocean. Its distribution overlaps widely, but slightly to the southern giant petrel (Macronectes giganteus).
As per Wikipedia, 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).
Northern giant petrel 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 Northern giant petrel is 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 a grey-brown body with the lighter colored forehead, sides of the face, and chin.
Bill of the Northern giant petrel is 90 to 110 mm (3.5-4.3 inches) long, a little longer than average on the southern giant petrel, and pinkish-yellow with a brownish tinge. Its eyes are gray.
The tarsus of the northern giant petrel is slightly taller than the southern species, but the wingspan is longer than the average in the south.
The juvenile Northern giant petrel or Macronectes halli is completely dark brown and lighter with age.
It can be distinguished from Macronectes giganteus at the top of the bill, which is green on the southern species.
The giant petrol of the north mainly feeds on carrion (dead penguin and pinniped), as well as fish, krill, squid and other cephalopods.
They will follow fishing boats and cruise ships and eat any discarded fish and waste from the ship. During the breeding season, males eat more carrion than females, females feed on pelagic sources.
They are extremely aggressive and will kill other marine birds (mostly penguin rats, sick or injured adult penguins and other marine birds), or even larger ones like an albatross.
Northern giant petrel moves to the same location as Southern Giant Petrels, but due to the breeding season of Northern Giant Petrels at different times.
This temporary split in habitat-use is thought to reduce intercultural competition, while sexual separation by women leads to more pelagic trips than males, reducing inter-race competition.
Birds begin breeding at an average age of ten and breed on the islands of the colonies, which they share with the giant petrel of the south. They breed six weeks earlier than their competitors.
Range and habitat
M. halli is pelagic and found throughout the southern oceans through Chile, Argentina, South Africa, and half of Australia, north, and south of the Antarctic convergence zones.
Over 4,500 pairs of nests are built on the islands of the South Georgia Group. They live in the Chatham Islands, Keroglin Islands, Crozet Islands, Macquarie Islands, and other areas.
Their overall range of the Northern giant petrel is 82,600,000 km2 (31,900,000 square miles).
According to 2001 estimates, there were 17,000 to 21,000 mature birds of this species. This number has grown over the past two decades, after expectations of a decline.
The IUCN has thus downgraded the Northern giant petrel from being under threat of lesser concern. Recent surveys have shown that most locations are growing in numbers except the Crozet Islands.
This is probably due to increased fish waste, better control over longline fishing, and more carrion from fur seals.