The sooty albatrosses are small
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 Pacifi ...
es from the
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
''Phoebetria''. There are two species, the
sooty albatross
The sooty albatross, dark-mantled sooty albatross or dark-mantled albatross,BirdLife International (2008b) (''Phoebetria fusca''), is a species of bird in the albatross family. They breed on sub-Antarctic islands and range at sea across the S ...
, ''Phoebetria fusca'', and the
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. The light-mantled a ...
, ''Phoebetria palpebrata''.
Systematics
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 (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial D ...
has shown that the taxon is related to the
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 usually called sooty albatrosses. They are restricted to the Sout ...
s, and that the two taxa are distinct from the
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 Paci ...
es and the
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 (the Laysan and black-footed albatrosses) nesting in the Northwestern Hawai ...
es.
Description
Both have distinctive blackish
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, ...
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 and are very narrow as well. The light-mantled, at and sometimes to , is larger than the sooty, at . 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
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 ...
s, are
colonial
Colonial or The Colonial may refer to:
* Colonial, of, relating to, or characteristic of a colony or colony (biology)
Architecture
* American colonial architecture
* French Colonial
* Spanish Colonial architecture
Automobiles
* Colonial (1920 au ...
, although they are less colonial than the other species of albatrosses. In fact, on some breeding islands (like
Tristan da Cunha
Tristan da Cunha (), colloquially Tristan, is a remote group of volcanic islands in the South Atlantic Ocean. It is the most remote inhabited archipelago in the world, lying approximately from Cape Town in South Africa, from Saint Helena ...
) 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
incubated 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 is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperature ...
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
Fledging is the stage in a flying animal's life between hatching or birth and becoming capable of flight.
This term is most frequently applied to birds, but is also used for bats. For altricial birds, those that spend more time in vulnerable c ...
. 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
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 ...
(Tristan da Cunha and
Gough Island
upright=1.3, Map of Gough island
Gough Island ( ), also known historically as Gonçalo Álvares, is a rugged volcanic island in the South Atlantic Ocean. It is a dependency of Tristan da Cunha and part of the British overseas territory of Sain ...
) and islands in the South
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 th ...
(the
Crozet Islands
The Crozet Islands (french: Îles Crozet; or, officially, ''Archipel Crozet'') 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 Antarcti ...
to
Kerguelen Island
The Kerguelen Islands ( or ; in French commonly ' but officially ', ), also known as the Desolation Islands (' in French), are a group of islands in the sub-Antarctic constituting one of the two exposed parts of the Kerguelen Plateau, a large ...
). At sea they forage from
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...
to
Australia
Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
, with a few records of birds reaching
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 ...
. 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 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 ...
and New Zealand's subantarctic islands. At sea it forages further south than the sooty to
Antarctica
Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest contine ...
, and around 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 ...
as far north as
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 ...
,
Tasmania
)
, nickname =
, image_map = Tasmania in Australia.svg
, map_caption = Location of Tasmania in AustraliaCoordinates:
, subdivision_type = Country
, subdi ...
and
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 countri ...
. 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 and once being recorded as deep as .
Conservation
The two species face similar threats,
introduced species
An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived there ...
that attack chicks and eggs, and falling victim to
longline fisheries
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''.[< ...]
. 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
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 inv ...
by the
IUCN
The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...
. The light-mantled albatross has not been as badly affected, and is considered
near threatened
A near-threatened species is a species which has been categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature as that may be vulnerable to endangerment in the near future, but it does not currently qualify fo ...
.
See also
*
List of albatross breeding locations
The following is a list of locations where albatrosses breed, together with a list of the species found at each location.
North Pacific Ocean
*Bonin Islands - black-footed, Laysan
*French Frigate Shoals - Laysan, black-footed
* Guadalupe Island ...
References
Further reading
*
*
*
{{Taxonbar, from=Q429508
Bird genera
Taxa named by Ludwig Reichenbach