The Northern Giant Petrels (Macronectes halli), also known as the Hall’s Giant Petrel, is a large seabird of the southern oceans. Its distribution overlaps broadly with the similar Southern Giant Petrel, though it overall is centered slightly further north.
Description
The Northern Giant Petrels averages 90 cm (35 in) in length. Its plumage consists of a grey-brown body with a lighter-colored forehead, sides of face, and chin. Its bill is between 90–105 mm (3.5–4.1 in) long and is pinkish yellow with a brown tip, and its eyes are grey.
The juvenile of this species is completely dark brown and lightens as it ages. It can be differentiated from the similar-colored Southern Giant Petrel by the top of the bill, which on the southern is green.
Range and habitat
They are pelagic (over sea) and fly throughout the southern oceans north of the Antarctic Convergence Zone, and north through Chile, Argentina, South Africa, and half of Australia.
They nest on islands with the South Georgia group with 4,500 pairs. They also nest on some of the Chatham Islands, Kerguelen Islands, Crozet Islands, Macquarie Island, of and others. Their overall occurrence range is 82,600,000 km2 (31,900,000 sq mi).
| Location | Population | Date | Trend |
| South Georgia | 4,500 pair | 2005 | Increasing 30% per 20 yr |
| Forty-Fours | 2,000 pair | 2000 | |
| Middle Sister | 80—100 pair | 2000 | |
| Kerguelen Islands | 1,450—1,800 pair | 1989 | |
| Crozet Islands | 1,300 pair | 1989 | Decreasing |
| Macquarie Island | 1,300 pair | Stable or Increasing | |
| Prince Edward Islands | 650 pair | Increasing | |
| Antipodes Island | 230 pair | 2003 | |
| Campbell Island, New Zealand | 230 pair | 2000 | |
| Auckland Islands | 50 pair | 2000 | |
| Total | 17,000—21,000 | 2001 | Increasing 34% per 10 yr |
Feeding
The Northern Giant Petrels feeds mainly on carrion (carcass) from penguins and pinniped, as well as krill, offal (= entrails and internal organs of butchered animals), cephalopods, and discarded fish and waste from ships. During breeding season, males eat more carrion than females with the females feeding on pelagic (over sea) sources.
Breeding
Birds start breeding on average of ten years of age, and breed on islands in colonies. Where they share islands with the Southern Giant Petrel, they breed six weeks earlier than their counterpart.
Conservation
Overall their population stands at between 17,000 and 21,000 mature birds, based on a 2001 estimate. This number has been increasing over the last two decades even though it was forecast to decrease.
This increase has allowed the IUCN to downgrade them from Near Threatened to Least Concern.
Recent surveys have shown that most locations are increasing in numbers except for Crozet Islands. This is probably due to increases in fish waste, better control on longline fishing, and more carrion (carcass of a dead animal) from Fur Seals.
Currently, this bird is listed in CMS Appendix II and ACAP Annex 1 (Bonn Convention). Plans are to maintain the surveys and counting of individuals, research movement and migrations, and continue the trend of lowering the bycatch deaths by current means, and if needed newer measures through CCAMLR, Conservation Management System (CMS), and FAO.
Taxonomy
The Northern Giant Petrels along with its counterpart, the Southern Giant Petrel, make up the Macronectes genus. They come from the Procellariiformes order, which are referred to as tube-nosed seabirds, due to their unique nose structure.
All tube noses have tubular nostrils, and all Procellariidae have openings on top of the upper portion of the bill. Procellariiformes also have between seven and nine distinct horny plates for their bill, and Petrels have one of these plates that form the hooked portion of their upper bill called their maxillary unguis.
They produce stomach oil made up of wax esters and triglycerides that are stored in the proventriculus (stomach). This is used against predators as well as an energy-rich food source for chicks and adults during their long flights.
Finally, they also have a salt gland that is situated above the nasal passage and helps desalinate their bodies, due to the high amount of ocean water that they imbibe. It excretes a high saline solution from their nose.
Etymology
Macronectes giganteus can be broken down as makros a Greek word meaning long or large and nēktēs meaning swimmer. Northern Giant Petrel starts with northern referring to their habitat being further north than their counterpart the Southern Giant Petrel, and Petrel refers to St. Peter and from the story of him walking on water, which refers to how they run on top of the water as they are getting airborne.
