The grey-headed albatross (''Thalassarche chrysostoma'') also known as the gray-headed mollymawk, is a large

seabird Seabirds (also known as marine birds) are birds that are adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same enviro ...

from the albatross

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 ...

. It has a

circumpolar Circumpolar may refer to: * Antarctic region ** Antarctic Circle ** the Antarctic Circumpolar Current ** Subantarctic ** List of Antarctic and subantarctic islands ** Antarctic Convergence ** Antarctic Circumpolar Wave ** Antarctic Ocean * Arctic ...

distribution, nesting on isolated islands in 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-small ...

and feeding at high latitudes, further south than any of the other mollymawks. Its name derives from its ashy-gray head, throat and upper neck.

Taxonomy

Mollymawks are a type of albatross that belong to the family

Diomedeidae 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 Pacif ...

from the order

Procellariiformes Procellariiformes is an order (biology), order of seabirds that comprises four family (biology), families: the albatrosses, the Procellariidae, petrels and shearwaters, and two families of storm petrels. Formerly called Tubinares and still call ...

, along with

shearwater Shearwaters are medium-sized long-winged seabirds in the petrel family Procellariidae. They have a global marine distribution, but are most common in temperate and cold waters, and are pelagic outside the breeding season. Description These tub ...

fulmar The fulmars are tubenosed seabirds of the family Procellariidae. The family consists of two extant species and two extinct fossil species from the Miocene. Fulmars superficially resemble gulls, but are readily distinguished by their flight on ...

storm petrel Storm-petrel may refer to one of two bird families, both in the order Procellariiformes, once treated as the same family. The two families are: * Northern storm petrels (''Hydrobatidae'') are found in the Northern Hemisphere, although some speci ...

s, and

diving petrel The diving petrels form a genus, ''Pelecanoides'', of seabirds in the family Procellariidae. There are four very similar species of diving petrels, distinguished only by small differences in the coloration of their plumage, habitat, and bill co ...

s. They share certain identifying features. First, they have nasal passages that attach to the upper bill called naricorns, although the nostrils of an albatross are on the sides of the bill. The bills of Procellariiformes are also unique in that they are split into between seven and nine horny plates. Finally, they produce a stomach oil made up of wax esters and

triglycerides A triglyceride (TG, triacylglycerol, TAG, or triacylglyceride) is an ester derived from glycerol and three fatty acids (from ''tri-'' and ''glyceride''). Triglycerides are the main constituents of body fat in humans and other vertebrates, as we ...

that is stored in the proventriculus. This is used against predators as well as an energy rich food source for chicks and for the adults during their long flights. They also have a

salt gland The salt gland is an organ for excreting excess salts. It is found in the cartilaginous fishes subclass elasmobranchii (sharks, rays, and skates), seabirds, and some reptiles. Salt glands can be found in the rectum of sharks. Birds and reptiles ...

situated above the nasal passage that helps desalinate their bodies, to compensate for the ocean water they imbibe. It excretes a concentrated brine from the nostrils.

Etymology

The name ''chrysostoma'' is derived from two

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

words. ''Khrusos'' means "gold" and ''stoma'' means "the mouth", in reference to its golden bill.

Description

The grey-headed albatross averages in length and in wingspan. Weight can range from , with a mean mass of . It has a dark ashy-grey head, throat, and upper neck, and its upper wings, mantle, and tail, are almost black. It has a white rump, underparts, and a white crescent behind its eyes. Its bill is black, with bright yellow upper and lower ridges, that shades to pink-orange at the tip. Its underwings are white with a lot of black on the leading edge and less on the trailing edge. Juveniles have a black bill and head and a darker nape. Its eye crescent is indistinct and its underwing is almost completely dark.BirdLife International (2008)

Range and habitat

Grey-headed albatrosses nest in colonies on several islands in the Southern Ocean, with large colonies on South Georgia in the South

Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe an ...

, and smaller colonies on Islas Diego Ramírez, Kerguelen Islands, Crozet Islands, Marion Island, and Prince Edward Islands in the

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by t ...

, Campbell Island and

Macquarie Island Macquarie Island is an island in the southwestern Pacific Ocean, about halfway between New Zealand and Antarctica. Regionally part of Oceania and politically a part of Tasmania, Australia, since 1900, it became a Tasmanian State Reserve in 197 ...

south of

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 smaller islands. It is the sixth-largest island count ...

, and

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 east a ...

. While breeding, they will forage for food within or south of the Antarctic Polar Frontal Zone.Prince, et al. (1998)Phillips, et al. (2004) Birds that roost in the Marion Island area forage for food in the sub-tropical zone.Nel, et al. (2001) Juveniles or non-breeding adults fly freely throughout all the southern oceans, north to 35°S.

Behaviour

Feeding

At sea the grey-headed albatross is highly

pelagic The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or w ...

, more so than other mollymawks, feeding in the open oceans rather than over the continental shelves. They feed predominantly on squid, taking also some fish, crustacea, carrion, cephalopods, and

lamprey Lampreys (sometimes inaccurately called lamprey eels) are an ancient extant lineage of jawless fish of the order Petromyzontiformes , placed in the superclass Cyclostomata. The adult lamprey may be characterized by a toothed, funnel-like s ...

s.Prince (1980)Cherel, et al. (2002)Xavier, et al. (2003)Arata, et al. (2004)

Krill Krill are small crustaceans of the order Euphausiacea, and are found in all the world's oceans. The name "krill" comes from the Norwegian word ', meaning "small fry of fish", which is also often attributed to species of fish. Krill are consi ...

is less important as a food source for this species, reflecting their more pelagic feeding range. They are capable of diving as deep as to chase prey, but do not do so frequently.

Reproduction

A single egg is laid in a large nest, typically built on steep slopes or cliffs with

tussock grass Tussock grasses or bunch grasses are a group of grass species in the family Poaceae. They usually grow as singular plants in clumps, tufts, hummocks, or bunches, rather than forming a sod or lawn, in meadows, grasslands, and prairies. As perenni ...

, and incubated for 72 days. Studies at South Georgia's Bird Island have shown that the growing chick is fed of food every 1.2 days, with the chick increasing in weight to around . Chicks then tend to lose weight before fledging, which happens after 141 days. Chick will generally not return to the colony for 6–7 years after fledging, and will not breed for the first time until several years after that. If a pair has managed to successfully raise a chick it will not breed in the following year, taking the year off. During this time spent away from the colony they can cover great distances, often circling the globe several times.

Conservation

The IUCN classifies this bird as

endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and in ...

due to rapidly declining numbers in South Georgia which holds around half the world's population. It has an occurrence range of and a breeding range of , with a population, estimated in 2004, of 250,000.Croxall & Gales (1998)Brooke, (2004) Estimates place 48,000 pairs at

South Georgia Island 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� ...

,Poncet, et al. (2006) 6,200 on Marion Island,Crawford, et al. (2003) 3,000 pairs on Prince Edward Islands,Ryan, et al. (2003) 7,800 pairs on Campbell Island,Moore (2004) 16,408 pairs in

,Arata & Morena (2002) 84 pairs on

, 5,940 on Crozet Island, and 7,905 on Kerguelen IslandsGales (1998) Populations have been shrinking based on different studies. Bird Island numbers have been reduced 20% to 30% in the last 30 years.Croxall et al. (1998) Marion Island registered 1.75% reduction per year until 1992 and now appears to be stable.Nel et al. (2002) Campbell Island has seen reduction of 79% to 87% since the 1940s.Taylor, (2000) Overall, the trends looks like a 30-40% reduction over 90 years (3 generations). Illegal or unregulated fishing in the

for the

Patagonian toothfish The Patagonian toothfish (''Dissostichus eleginoides'') is a species of notothen found in cold waters () between depths of in the southern Atlantic, Pacific, and Indian Oceans and Southern Ocean on seamounts and continental shelves around most ...

, ''Dissostichus eleginoides'' resulted in 10–20,000 dead albatrosses, mainly this species, in 1997 and 1998.CCAMLR (1997)CCAMLR (1998)Nel et al. (2002a)

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''.< ...

is responsible for other deaths.Clay et al. (2019) To assist this species, studies are being undertaken at most of the islands. Also, Prince Edward Islands is a special nature preserve, and Campbell Island and

are

World Heritage Site A World Heritage Site is a landmark or area with legal protection by an international convention administered by the United Nations Educational, Scientific and Cultural Organization (UNESCO). World Heritage Sites are designated by UNESCO for h ...

Footnotes

References

* * * * * * * * * * * * * * * del Hoyo, Josep, Elliott, Andrew & Sargatal, Jordi (1992). ''Handbook of Birds of the World'' Vol 1. Barcelona:Lynx Edicions, * * * * * * * * * * * * * * *

External links

Species factsheet
- BirdLife International
Photos and fact file
- ARKive
Photos
- Christopher Taylor Nature Photography {{Authority control grey-headed albatross Birds of Argentina Birds of Chile Birds of New Zealand Birds of islands of the Atlantic Ocean Vulnerable fauna of Australia Birds of the Indian Ocean Fauna of the Prince Edward Islands Birds of Uruguay Birds of the Southern Ocean Birds of the Campbell Islands grey-headed albatross Birds of subantarctic islands