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The northern giant petrel (''Macronectes halli''), also known as Hall's giant petrel, is a large predatory seabird of the southern oceans. Its distribution overlaps broadly, but is slightly north of, the similar southern giant petrel (''Macronectes giganteus'').


Taxonomy

The northern giant petrel was formally described in 1912 by the Australian born ornithologist Gregory Mathews as a subspecies of the southern giant petrel with the
trinomial name In biology, trinomial nomenclature refers to names for taxa below the rank of species. These names have three parts. The usage is different in zoology and botany. In zoology In zoological nomenclature, a trinomen (), trinominal name, or te ...
''Macronectes giganteus halli''. The specific epithet ''halli'' was chosen to honour the Australian ornithologist Robert Hall who had described the birds breeding on the Kerguelen Islands. The northern giant petrel is now considered to be a separate species and has the
binomial name In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...
''Macronectes halli''. It is
monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...
: no subspecies are recognised. The genus name combines the
Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic p ...
''makros'' meaning "great" and ''nēktēs'' meaning "swimmer". The name "petrel" refers to the Biblical account of
Saint Peter ) (Simeon, Simon) , birth_date = , birth_place = Bethsaida, Gaulanitis, Syria, Roman Empire , death_date = Between AD 64–68 , death_place = probably Vatican Hill, Rome, Italia, Roman Empire , parents = John (or Jonah; Jona) , occupa ...
walking on water, referring to the way these birds run on top of the water as they are getting airborne. The two giant petrel species make up the genus '' Macronectes''. They belong to the
order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...
Procellariiformes, the tube-nosed seabirds or petrels. All tube-noses have tubular nostrils, and all those in the
family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
Procellariidae, the true petrels, have their nostrils united along the top of the bill. Procellariform birds have between seven and nine distinct horny plates for their bill, and in petrels one of these plates forms the hooked portion of their upper bill called the maxillary unguis. They produce a stomach oil made up of
wax ester A wax ester (WE) is an ester of a fatty acid and a fatty alcohol. Wax esters comprise the main components of three commercially important waxes: carnauba wax, candelilla wax, and beeswax.. Wax esters are formed by combining one fatty acid with ...
s and triglycerides that is stored in the proventriculus. This can be sprayed out of their mouths as a defence 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 sea water that they imbibe. It excretes a concentrated saline solution from their nostrils.


Description

The northern giant petrel averages in length, with a range of , possessing a wingspan of . 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 and 43 females average .''CRC Handbook of Avian Body Masses, 2nd Edition'' by John B. Dunning Jr. (Editor). CRC Press (2008), . The smallest-bodied are on the
Chatham Islands The Chatham Islands ( ) ( Moriori: ''Rēkohu'', 'Misty Sun'; mi, Wharekauri) are an archipelago in the Pacific Ocean about east of New Zealand's South Island. They are administered as part of New Zealand. The archipelago consists of about t ...
, where 19 males averaged and 21 females averaged .Carlos, C. J., & Voisin, J. F. (2008). ''Identifying giant petrels, Macronectes giganteus and M. halli, in the field and in the hand''. Publishing Editor, 1. Overall, weight for the species can range from . Its
plumage Plumage ( "feather") is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, ...
consists of grey-brown body with lighter coloured forehead, sides of face, and chin. Its bill is between 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.


Distribution and habitat

The northern giant petrel is pelagic and is found throughout the
Southern Ocean The Southern Ocean, also known as the Antarctic Ocean, comprises the southernmost waters of the World Ocean, generally taken to be south of 60° S latitude and encircling Antarctica. With a size of , it is regarded as the second-smal ...
north of the Antarctic Convergence Zone, and north through
Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the eas ...
,
Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, t ...
,
South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring count ...
,
New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 List of islands of New Zealand, smaller islands. It is the ...
, and half of Australia. Over 4,500 pairs nest on islands in the
South Georgia South Georgia ( es, Isla San Pedro) is an island in the South Atlantic Ocean that is part of the British Overseas Territory of South Georgia and the South Sandwich Islands. It lies around east of the Falkland Islands. Stretching in the east ...
group. They also nest on some of the
Chatham Islands The Chatham Islands ( ) ( Moriori: ''Rēkohu'', 'Misty Sun'; mi, Wharekauri) are an archipelago in the Pacific Ocean about east of New Zealand's South Island. They are administered as part of New Zealand. The archipelago consists of about t ...
, Kerguelen Islands, Crozet Islands, Macquarie Island and others. Their overall range is .


Behaviour


Feeding

The northern giant petrel feeds mainly on
carrion Carrion () is the decaying flesh of dead animals, including human flesh. Overview Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters (or scavengers) include crows, vultures ...
(dead penguins and
pinniped Pinnipeds (pronounced ), commonly known as seals, are a widely range (biology), distributed and diverse clade of carnivorous, fin-footed, semiaquatic, mostly marine mammal, marine mammals. They comprise the extant taxon, extant family (biology ...
s), as well as fish, krill,
squid True squid are molluscs with an elongated soft body, large eyes, eight arms, and two tentacles in the superorder Decapodiformes, though many other molluscs within the broader Neocoleoidea are also called squid despite not strictly fitting ...
, and other cephalopods. They will follow
fishing boats A fishing vessel is a boat or ship used to catch fish in the sea, or on a lake or river. Many different kinds of vessels are used in commercial, artisanal and recreational fishing. The total number of fishing vessels in the world in 2016 w ...
and
cruise ships Cruise ships are large passenger ships used mainly for vacationing. Unlike ocean liners, which are used for transport, cruise ships typically embark on round-trip voyages to various ports-of-call, where passengers may go on Tourism, tours know ...
, eating any discarded fish and waste from the ships. During the breeding season, males eat more carrion than females, with the females feeding on pelagic sources. They are extremely aggressive and will kill other seabirds (mostly penguin chicks, sick or injured adult penguins and the chicks of other seabirds), even those as large as an
albatross Albatrosses, of the biological family Diomedeidae, are large seabirds related to the procellariids, storm petrels, and diving petrels in the order Procellariiformes (the tubenoses). They range widely in the Southern Ocean and the North P ...
.BirdLife International (2009) 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 segregation in habitat-use reduces interspecific competition, whilst sexual segregation, due to females making more pelagic trips than males, reduces intraspecific competition.


Breeding

Birds start breeding at an average age of ten years, and breed on islands in
colonies In modern parlance, a colony is a territory subject to a form of foreign rule. Though dominated by the foreign colonizers, colonies remain separate from the administration of the original country of the colonizers, the '' metropolitan state' ...
, which they share with the southern giant petrel. They breed six weeks earlier than their counterparts.


Conservation

In a 2001 estimate, this species had between 17,000 and 21,000 mature birds. This number has been increasing over the last two decades, after being expected to decrease. The IUCN thus downgraded them from near threatened to
least concern A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. Th ...
. Recent surveys have shown that most locations are increasing in numbers, except for the Crozet Islands. This is probably due to increases in fish waste, better control on
longline fishing Longline fishing, or longlining, is a commercial fishing angling technique that uses a long ''main line'' with fish bait, baited fish hook, hooks attached at intervals via short branch lines called ''snoods'' or ''gangions''.< ...
, and more
carrion Carrion () is the decaying flesh of dead animals, including human flesh. Overview Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters (or scavengers) include crows, vultures ...
from
fur seals Fur seals are any of nine species of pinnipeds belonging to the subfamily Arctocephalinae in the family '' Otariidae''. They are much more closely related to sea lions than true seals, and share with them external ears ( pinnae), relatively ...
. Currently, this bird is listed on CMS Appendix II and ACAP Annex 1. Future plans are to maintain surveys and counting of individuals, research movement and migration, and continue lowering the
bycatch Bycatch (or by-catch), in the fishing industry, is a fish or other marine species that is caught unintentionally while fishing for specific species or sizes of wildlife. Bycatch is either the wrong species, the wrong sex, or is undersized or juven ...
deaths by current means and if needed newer measures through CCAMLR, CMS, and FAO.


References


Sources

* * * * *


External links


Species factsheet
by BirdLife International
Photos
by Christopher Taylor Nature Photography * Southern and Northern Giant Petrels
Species text in The Atlas of Southern African Birds
* Northern giant petrel discussed in RNZ ''Critter of the Week''
7 July 2017
{{Taxonbar, from=Q276212 northern giant petrel Birds of Uruguay Birds of Patagonia Birds of Southern Africa Birds of New South Wales Birds of South Australia Birds of Victoria (Australia) Birds of Western Australia Birds of Tasmania Birds of New Zealand Birds of subantarctic islands northern giant petrel