Northern Giant Petrels or Hall's Giant Petrels

Petrels

Northern giant petrel, Kerguelen Island, Indian Ocean


Northern Giant Petrel (Macronectes halli), also known as the Hall's Giant PetrelThe Northern Giant Petrel (Macronectes halli), also known as the Hall's Giant Petrel, is a 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 Petrel averages 90 cm (35 in) in length. Its plumage consists of grey-brown body with 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 pair. They also nest on some of the Chatham Islands, Kerguelen Islands, Crozet Islands, Macquarie Island and others. Their overall occurrence range is 82,600,000 km2 (31,900,000 sq mi).


Breeding Population and Trends
LocationPopulationDateTrend
South Georgia4,500 pair2005Increasing 30% per 20 yr
Forty-Fours2,000 pair2000
Middle Sister80—100 pair2000
Kerguelen Islands1,450—1,800 pair1989
Crozet Islands1,300 pair1989Decreasing
Macquarie Island1,300 pairStable or Increasing
Prince Edward Islands650 pairIncreasing
Antipodes Island230 pair2003
Campbell Island, New Zealand230 pair2000
Auckland Islands50 pair2000
Total17,000—21,0002001Increasing 34% per 10 yr

Feeding

The Northern Giant Petrel 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.

Northern Giant Petrel (Macronectes halli), also known as the Hall's Giant Petrel


Northern Giant Petrel (Macronectes halli), also known as the Hall's Giant PetrelBreeding

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 on CMS Appendix II and ACAP Annex 1 (Bonn Convention). Future plans are to maintain the surveys and counting of individuals, researching movement and migrations, continuing the trend of lowering the bycatch deaths by current means and if needed newer measures through CCAMLR, Conservation Management System (CMS), and FAO.


Northern Giant Petrel (Macronectes halli), also known as the Hall's Giant PetrelTaxonomy

The Northern Giant Petrel 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 the 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 a stomach oil made up of wax esters and triglycerides that is stored in the proventriculus (stomach). This is used against predators as well as an energy rich food source for chicks and for the 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.

Northern Giant Petre


Northern Giant Petrel (Macronectes halli), also known as the Hall's Giant PetrelEtymology

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.


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