Sooty albatross
Encyclopedia
The sooty albatrosses are small albatross
es from the genus
Phoebetria. There are two species, the Sooty Albatross
, Phoebetria fusca, and the Light-mantled Albatross
, Phoebetria palpebrata. The sooties have long been considered distinct from the rest of the other albatrosses, and have retained their generic status through the many revisions of the family over the last 150 years. They have traditionally been thought of as primitive, sharing some morphological features with the other petrel families. However, molecular work examining the mitochondrial DNA
has shown that the taxon is related to the mollymawk
s, and that the two taxa are distinct from the great albatross
es and the North Pacific albatross
es.
over the head, wings and bellies. The Sooty Albatross has a dark back and mantle as well, whereas the Light-mantled has an ashy-grey mantle, back and rump. The two species can also be told apart by the narrow yellow line on the Sooty's bill. Despite the differences between the two species they can be hard to tell apart at sea, especially in poor light. Both species have a white incomplete eye-ring, dark bills and grey feet. They are among the smallest albatrosses, with wingspans of 200 cm (78.7 in) and are very narrow as well. The Light-mantled, at 2.5 to 3.7 kg (5.5 to 8.2 lb) and sometimes to 4.6 kg (10.1 lb), is larger than the Sooty, at 2.4 to 2.7 kg (5.3 to 6 lb). Unique amongst the albatrosses they have long stiff wedge shaped tails, the purpose of which is unclear but seems to be related to their ability to dive for food.
s, are colonial, although they are less colonial than the other species of albatrosses. In fact, on some breeding islands (like Tristan da Cunha
) they may nest in very small groups or clusters of two to five nests, and the Light-mantled will even nest singly. This is in part due to the influence of humans, and in part due to their tendency to nest on cliffs, unlike the flatter ground preferred by other albatrosses. Both species build cone shaped nests and lay a single egg. Eggs are incubate
d for 70 days, by both parents, the male taking the first stint after laying (lasting 11 days) thereafter both parents taking it in turns of 7 days. After hatching the chick is brooded for 20 days until it is able to thermoregulate
on its own, after which both parents undertake the task of feeding it, on average bringing food to the chick every three days. The chick is fed for about 160 days, until it is able to fledge
. There is no parental care after fledging. They are able to complete a breeding cycle in under a year, but do not breed in consecutive years, instead taking a year off and returning to breed every two years. Around 22% of the Sooty Albatrosses survive until adulthood (there are no figures for Light-mantled). Both species return to the breeding colony after 7–10 years of fledging, and begin to breed a few years later.
) and islands in the South Indian Ocean
(the Crozet Islands
to Kerguelen Island). At sea they forage from South America
to Australia
, with a few records of birds reaching New Zealand
. The Light-mantled Albatross has a wider distribution, nesting on South Georgia in the Atlantic, many of the same islands in the Indian Ocean, Macquarie Island
and New Zealand's sub-Antarctic islands. At sea it forages further south than the Sooty to Antarctica, and around the Southern Ocean
as far north as Chile
, Tasmania
and South Africa
. At sea they often eat more fish as opposed to squid than other albatross species, and the sooties also readily take carrion and particularly other seabirds. They also are the deepest diving of the albatross, often diving to 5m and once being recorded as deep as 12m.
that attack chicks and eggs, and falling victim to long-line fisheries
. These threats, combined with some historic harvesting of the birds and chicks, has led to an estimated 75% population decline in the Sooty Albatross over the last 90 years (to around 40,000 birds), which has led to it being listed as an endangered species
by the IUCN. The Light-mantled Albatross has not been as badly affected, and is considered near threatened
.
Albatross
Albatrosses, of the biological family Diomedeidae, are large seabirds allied to the procellariids, storm-petrels and diving-petrels in the order Procellariiformes . They range widely in the Southern Ocean and the North Pacific...
es from the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Phoebetria. There are two species, the Sooty Albatross
Sooty Albatross
The Sooty Albatross, Dark-mantled Sooty Albatross or Dark-mantled Albatross, Phoebetria fusca, is a species of bird in the albatross family...
, Phoebetria fusca, and the Light-mantled Albatross
Light-mantled Albatross
The Light-mantled Albatross, Phoebetria palpebrata, also known as the Grey-mantled Albatross or the Light-mantled Sooty Albatross, is a small albatross in the genus Phoebetria, which it shares with the Sooty Albatross...
, Phoebetria palpebrata. The sooties have long been considered distinct from the rest of the other albatrosses, and have retained their generic status through the many revisions of the family over the last 150 years. They have traditionally been thought of as primitive, sharing some morphological features with the other petrel families. However, molecular work examining the mitochondrial DNA
Mitochondrial DNA
Mitochondrial DNA is the DNA located in organelles called mitochondria, structures within eukaryotic cells that convert the chemical energy from food into a form that cells can use, adenosine triphosphate...
has shown that the taxon is related to the mollymawk
Mollymawk
The mollymawks are a group of medium sized albatrosses that form the genus Thalassarche. The name has sometimes been used for the genus Phoebetria as well, but these are correctly called sooty albatrosses. They are restricted to the Southern Hemisphere, where they are the most common of the...
s, and that the two taxa are distinct from the great albatross
Great albatross
The great albatrosses are seabirds in the genus Diomedea in the albatross family. The genus Diomedea formerly included all albatrosses except the sooty albatrosses, but in 1996 the genus was split with the mollymawks and the North Pacific albatrosses both being elevated to separate genera...
es and the North Pacific albatross
North Pacific albatross
The North Pacific albatrosses are large seabirds from the genus Phoebastria in the albatross family. They are the most tropical of the albatrosses, with two species nesting in North Western Hawaiian island chain, one on sub-tropical islands south of Japan , and one nesting on the equator The North...
es.
Description
Both have distinctive blackish plumagePlumage
Plumage refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage vary between species and subspecies and can also vary between different age classes, sexes, and season. Within species there can also be a...
over the head, wings and bellies. The Sooty Albatross has a dark back and mantle as well, whereas the Light-mantled has an ashy-grey mantle, back and rump. The two species can also be told apart by the narrow yellow line on the Sooty's bill. Despite the differences between the two species they can be hard to tell apart at sea, especially in poor light. Both species have a white incomplete eye-ring, dark bills and grey feet. They are among the smallest albatrosses, with wingspans of 200 cm (78.7 in) and are very narrow as well. The Light-mantled, at 2.5 to 3.7 kg (5.5 to 8.2 lb) and sometimes to 4.6 kg (10.1 lb), is larger than the Sooty, at 2.4 to 2.7 kg (5.3 to 6 lb). Unique amongst the albatrosses they have long stiff wedge shaped tails, the purpose of which is unclear but seems to be related to their ability to dive for food.
Reproduction
The two species, like most seabirdSeabird
Seabirds are birds that have 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 environmental problems and feeding niches have resulted in similar adaptations...
s, are colonial, although they are less colonial than the other species of albatrosses. In fact, on some breeding islands (like Tristan da Cunha
Tristan da Cunha
Tristan da Cunha is a remote volcanic group of islands in the south Atlantic Ocean and the main island of that group. It is the most remote inhabited archipelago in the world, lying from the nearest land, South Africa, and from South America...
) they may nest in very small groups or clusters of two to five nests, and the Light-mantled will even nest singly. This is in part due to the influence of humans, and in part due to their tendency to nest on cliffs, unlike the flatter ground preferred by other albatrosses. Both species build cone shaped nests and lay a single egg. Eggs are incubate
Avian incubation
Incubation refers to the process by which certain oviparous animals hatch their eggs, and to the development of the embryo within the egg. The most vital factor of incubation is the constant temperature required for its development over a specific period. Especially in domestic fowl, the act of...
d for 70 days, by both parents, the male taking the first stint after laying (lasting 11 days) thereafter both parents taking it in turns of 7 days. After hatching the chick is brooded for 20 days until it is able to thermoregulate
Thermoregulation
Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different...
on its own, after which both parents undertake the task of feeding it, on average bringing food to the chick every three days. The chick is fed for about 160 days, until it is able to fledge
Fledge
Fledge is the stage in a young bird's life when the feathers and wing muscles are sufficiently developed for flight. It also describes the act of a chick's parents raising it to a fully grown state...
. There is no parental care after fledging. They are able to complete a breeding cycle in under a year, but do not breed in consecutive years, instead taking a year off and returning to breed every two years. Around 22% of the Sooty Albatrosses survive until adulthood (there are no figures for Light-mantled). Both species return to the breeding colony after 7–10 years of fledging, and begin to breed a few years later.
Range and habitat
Sooty Albatrosses nest on islands in the South Atlantic (Tristan da Cunha and Gough IslandGough Island
Gough Island , also known historically as Gonçalo Álvares or Diego Alvarez, is a volcanic island in the South Atlantic Ocean. It is a dependency of Tristan da Cunha and part of the British overseas territory of Saint Helena, Ascension and Tristan da Cunha...
) and islands in the South Indian Ocean
Indian Ocean
The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...
(the Crozet Islands
Crozet Islands
The Crozet Islands are a sub-antarctic archipelago of small islands in the southern Indian Ocean. They form one of the five administrative districts of the French Southern and Antarctic Lands.-Geography:...
to Kerguelen Island). At sea they forage from South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
to Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
, with a few records of birds reaching New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
. The Light-mantled Albatross has a wider distribution, nesting on South Georgia in the Atlantic, many of the same islands in the Indian Ocean, Macquarie Island
Macquarie Island
Macquarie Island lies in the southwest corner of the Pacific Ocean, about half-way between New Zealand and Antarctica, at 54°30S, 158°57E. Politically, it has formed part of the Australian state of Tasmania since 1900 and became a Tasmanian State Reserve in 1978. In 1997 it became a world heritage...
and New Zealand's sub-Antarctic islands. At sea it forages further south than the Sooty to Antarctica, and around the Southern Ocean
Southern Ocean
The Southern Ocean comprises the southernmost waters of the World Ocean, generally taken to be south of 60°S latitude and encircling Antarctica. It is usually regarded as the fourth-largest of the five principal oceanic divisions...
as far north as Chile
Chile
Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...
, Tasmania
Tasmania
Tasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart...
and South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
. At sea they often eat more fish as opposed to squid than other albatross species, and the sooties also readily take carrion and particularly other seabirds. They also are the deepest diving of the albatross, often diving to 5m and once being recorded as deep as 12m.
Conservation
The two species face similar threats, introduced speciesIntroduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
that attack chicks and eggs, and falling victim to long-line fisheries
Long-line fishing
Longline fishing is a commercial fishing technique. It uses a long line, called the main line, with baited hooks attached at intervals by means of branch lines called "snoods". A snood is a short length of line, attached to the main line using a clip or swivel, with the hook at the other end....
. These threats, combined with some historic harvesting of the birds and chicks, has led to an estimated 75% population decline in the Sooty Albatross over the last 90 years (to around 40,000 birds), which has led to it being listed as an endangered species
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
by the IUCN. The Light-mantled Albatross has not been as badly affected, and is considered near threatened
Near Threatened
Near Threatened is a conservation status assigned to species or lower taxa that may be considered threatened with extinction in the near future, although it does not currently qualify for the threatened status...
.