Tristan albatross

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Tristan albatross
Tristan Albatross (1).jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Procellariiformes
Family: Diomedeidae
Genus: Diomedea
Species:
D. dabbenena
Binomial name
Diomedea dabbenena
Mathews, 1929 [2]
Synonyms

Diomedea exulans dabbenena Mathews, 1929 [2]

The Tristan albatross (Diomedea dabbenena) is a large seabird from the albatross family. One of the great albatrosses of the genus Diomedea, it was only widely recognised as a full species in 1998. [3]

Taxonomy

Albatrosses belong to the family Diomedeidae of the order Procellariiformes, along with shearwaters, petrels, storm petrels, and diving petrels. They share certain identifying features. First, they have nasal passages that attach to the upper bill called naricorns, although the nostrils on the albatross are on the sides of the bill. The bills of Procellariiformes are also unique in that they are split into between 7 and 9 horny plates. Albatrosses also produce a stomach oil made up of wax esters and triglycerides 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. [4]

While not all scientists believe it is a full species with some retaining it as a subspecies of the wandering albatross (now the snowy albatross), a 2004 study of the mitochondrial DNA of the wandering albatross species complex [5] supported the split. Other studies have shown it to be the most genetically distinct member of the wandering albatross species complex. [6] This may be due to it diverging from their common ancestor before all its relatives, or because it underwent particularly strong genetic drift. Among the major experts, BirdLife International has split this species, [7]

Etymology

Diomedea refers to Diomedes, whose companions turned to birds. [8] The epitheton dabbenena refers to Roberto Dabbene, Italian-Argentine ornithologist.

Description

The Tristan albatross is practically indistinguishable from the snowy albatross at sea but is smaller and has a slightly darker back. It is 110 cm (43 in) from beak to tail [9] and has a wingspan of up to 3.05 m (10.0 ft). [10] The Tristan albatross also never attains the full white plumage of the snowy albatross, and its bill is about 25 mm (0.98 in) shorter. [7]

Distribution and habitat

Due to the difficulty in distinguishing them from snowy albatrosses, their distribution at sea is still not fully known, but the use of satellite tracking has shown that they forage widely in the South Atlantic, with males foraging west of the breeding islands towards South America and females to the east towards Africa. There have been sightings near Brazil and also off the coast of Australia. [7]

Tristan albatrosses are endemic to the islands of the Tristan da Cunha group and more specifically Gough Island. The majority of the world's population nest on Gough Island, around 1500 pairs. On some years a pair breeds on Inaccessible Island.

Behavior

The Tristan albatross feeds on fish and cephalopods.

They breed biennially and will nest in wet heath from 400 to 700 m (1,300–2,300 ft) in elevation. [7] They are monogamous, and do not start breeding until they are about 10 years old. [4]

Conservation

They were formerly threatened by introduced species, rats, cats and pigs, but these have now been removed from their breeding islands. However, this resulted in the population of mice, Mus musculus , increasing to the point where they would eat and kill albatross chicks en masse. [11] Even though the chicks are huge compared to the mice, they do not know how to defend themselves appropriately. Today the main threat to the species is believed to be long-line fishing and these mice. Recent counts suggest that the population on Gough has decreased by 28% over 46 years, whereas population modelling predicts annual decline rates of 2.9–5.3%. More recent modelling, conducted over three generations since 1980, suggests a decline equivalent to a >96% reduction in population size over three generations, since declines began. The rate of decline is therefore placed here in the band of 80–100% over three generations (86 years). [7]

Formerly classified as an endangered species by the IUCN, [12] it was suspected to be more threatened than generally assumed and undergoing a marked decline. Following the evaluation of its status, this was found to be correct, and the Tristan albatross was consequently uplisted to Critically Endangered status in 2008. [1] They have an occurrence range of 14,000,000 km2 (5,400,000 sq mi) and a breeding range of 80 km2 (31 sq mi). [7]

Related Research Articles

<span class="mw-page-title-main">Procellariiformes</span> Order of birds

Procellariiformes is an order of seabirds that comprises four families: the albatrosses, the petrels and shearwaters, and two families of storm petrels. Formerly called Tubinares and still called tubenoses in English, procellariiforms are often referred to collectively as the petrels, a term that has been applied to all members of the order, or more commonly all the families except the albatrosses. They are almost exclusively pelagic, and have a cosmopolitan distribution across the world's oceans, with the highest diversity being around New Zealand.

<span class="mw-page-title-main">Snowy albatross</span> Species of bird

The snowy albatross, also known as the white-winged albatross or goonie, is a large seabird from the family Diomedeidae; they have a circumpolar range in the Southern Ocean. It is the most recently described species of albatross and was long considered to be the same species as the Tristan albatross and the Antipodean albatross. Together with the Amsterdam albatross, it forms the wandering albatross species complex. When the complex was split into four species, the English name of the nominate form was changed from wandering albatross to snowy albatross.

<span class="mw-page-title-main">Black-browed albatross</span> Large seabird of the albatross family Diomedeidae

The black-browed albatross, also known as the black-browed mollymawk, is a large seabird of the albatross family Diomedeidae; it is the most widespread and common member of its family.

<span class="mw-page-title-main">Waved albatross</span> Species of bird

The waved albatross, also known as Galapagos albatross, is one of three species of the family Diomedeidae that occur in the tropics. When they forage, they follow a straight path to a single site off the coast of Peru, about 1,000 km (620 mi) to the east. During the non-breeding season, these birds reside primarily on the Ecuadorian and Peruvian coasts.

<span class="mw-page-title-main">Chatham albatross</span> Species of bird

The Chatham albatross, also known as the Chatham mollymawk or Chatham Island mollymawk, is a medium-sized black-and-white albatross which breeds only on The Pyramid, a large rock stack in the Chatham Islands, New Zealand (Aotearoa). It is sometimes treated as a subspecies of the shy albatross Thalassarche cauta. It is the smallest of the shy albatross group.

<span class="mw-page-title-main">Black-footed albatross</span> Species of bird

The black-footed albatross is a large seabird of the albatross family Diomedeidae from the North Pacific. All but 2.5% of the population is found among the Northwestern Hawaiian Islands. It is one of three species of albatross that range in the northern hemisphere, nesting on isolated tropical islands. Unlike many albatrosses, it is dark plumaged.

<span class="mw-page-title-main">Sooty albatross</span> Seabird in the family Diomedeidae

The sooty albatross, also known to sailors as the Quaker, is a species of marine bird belonging to the albatross family Diomedeidae. It is a medium-sized albatross that sports a sooty-brown or sooty-black color. It can be found in the southern Atlantic Ocean, the southern Indian Ocean, and the Southern Ocean. This bird scavenges for squid, fish, and carrion. Like other albatrosses, these birds mate for life and return to the same breeding spots every season. A single pair will mate every other year on a variety of islands in the southern Atlantic Ocean and the southern Indian Ocean islands. This bird is an endangered species and conservation efforts are taking place.

<span class="mw-page-title-main">Amsterdam albatross</span> Large bird which breeds only on Amsterdam Island in the southern Indian Ocean

The Amsterdam albatross or Amsterdam Island albatross,, is a large albatross which breeds only on Amsterdam Island in the southern Indian Ocean. It was only described in 1983, and was thought by some researchers to be a subspecies of the wandering albatross, D. exulans. BirdLife International and the IOC recognize it as a species, James Clements does not, and the SACC has a proposal on the table to split the species. More recently, mitochondrial DNA comparisons between the Amsterdam albatross, the wandering albatross Diomedea exulans, the Antipodean albatross D. antipodensis and the Tristan albatross D. dabbenena, provide clear genetic evidence that the Amsterdam albatross is a separate species.

<span class="mw-page-title-main">Grey-headed albatross</span> Species of bird

The grey-headed albatross also known as the gray-headed mollymawk, is a large seabird from the albatross family. It has a circumpolar distribution, nesting on isolated islands in the Southern Ocean 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.

<span class="mw-page-title-main">Great albatross</span> Genus of birds

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.

<span class="mw-page-title-main">Shy albatross</span> Species of bird

The shy albatross, also known as shy mollymawk, is a medium-sized albatross that breeds on three remote islands off the coast of Tasmania, Australia, in the southern Indian Ocean. Its lifespan is about 60 years, and it has been seen as far afield as South Africa and the Pacific coast of the United States. As of June 2020, the species is listed as "Endangered" in Australia; there are thought to be 15,000 pairs of shy albatross left. It is Australia's only endemic albatross.

<span class="mw-page-title-main">White-capped albatross</span> Subspecies of bird

The white-capped albatross is a mollymawk that breeds on the islands off of New Zealand. Not all experts agree that this form should be recognized as a separate species from the shy albatross, Thalassarche cauta. It is a medium-sized black, slate gray, and white albatross and is the largest of the mollymawks.

<span class="mw-page-title-main">Buller's albatross</span> Species of bird

Buller's albatross or Buller's mollymawk, is a small mollymawk in the albatross family.

<span class="mw-page-title-main">Campbell albatross</span> Species of bird

The Campbell albatross or Campbell mollymawk, is a medium-sized mollymawk in the albatross family. It breeds only on Campbell Island and the associated islet of Jeanette Marie, in a small New Zealand island group in the South Pacific. It is sometimes considered a subspecies of the black-browed albatross. It is a medium-sized black and white albatross with a pale yellow iris.

<span class="mw-page-title-main">Antipodean albatross</span> Species of bird

The Antipodean albatross is a large seabird in the albatross family. Antipodean albatrosses are smaller than snowy albatrosses, and breed in predominantly brown plumage, but are otherwise difficult to distinguish from young snowy albatrosses.

<span class="mw-page-title-main">Atlantic yellow-nosed albatross</span> Large seabird from the south Atlantic

The Atlantic yellow-nosed albatross is a large seabird in the albatross family Diomedeidae.

<span class="mw-page-title-main">Northern royal albatross</span> Species of bird

The northern royal albatross or toroa, is a large seabird in the albatross family. It was split from the closely related southern royal albatross as recently as 1998, though not all scientists support that conclusion and some consider both of them to be subspecies of the royal albatross.

<span class="mw-page-title-main">Southern royal albatross</span> Species of bird

The southern royal albatross or toroa, is a large seabird from the albatross family. At an average wingspan of above 3 m (9.8 ft), it is one of the two largest species of albatross, together with the wandering albatross. Recent studies indicate that the southern royal albatross may, on average, be somewhat larger than the wandering albatross in mass and have a similar wingspan, although other sources indicate roughly similar size for the two species and the wandering species may have a larger average wingspan in some colonies.

<span class="mw-page-title-main">Albatross</span> Family of large seabirds

Albatrosses, of the biological family Diomedeidae, are large seabirds related to the procellariids, storm petrels, and diving petrels in the order Procellariiformes. They range widely in the Southern Ocean and the North Pacific. They are absent from the North Atlantic, although fossil remains show they once occurred there and occasional vagrants are found. Albatrosses are among the largest of flying birds, and species of the genus Diomedea have the longest wingspans of any extant birds, reaching up to 3.7 m (12 ft). The albatrosses are usually regarded as falling into four genera, but disagreement exists over the number of species.

<span class="mw-page-title-main">Grey petrel</span> Species of bird

The grey petrel, also called the brown petrel, pediunker or grey shearwater is a species of seabird in the Procellariidae, or petrel family. It is pelagic and occurs in the open seas of the Southern Hemisphere, mainly between 32°S and 58°S.

References

  1. 1 2 BirdLife International (2018). "Diomedea dabbenena". IUCN Red List of Threatened Species . 2018: e.T22728364A132657527. doi: 10.2305/IUCN.UK.2018-2.RLTS.T22728364A132657527.en . Retrieved 19 November 2021.
  2. 1 2 BirdLife International (2008b)
  3. Robertson, C. J. R. & Nunn, G. B. (1998)
  4. 1 2 Double, M. C. (2003)
  5. Burg & Croxall (2004)
  6. Brooke, M. (2004)
  7. 1 2 3 4 5 6 BirdLife International (2008a)
  8. Gotch, A. F. (1995)
  9. "Tristan albatross - Diomedea dabbenena: Species Information - ARKive". Archived from the original on 2008-09-05. Retrieved 2008-09-19.?
  10. "Diomedea dabbenena — Tristan Albatross". Species Profile and Threats Database. Australian Government - Department of Climate Change, Energy, the Environment and Water. Retrieved 10 October 2023.
  11. Wanless, R. M. et al., (7 June 2007)
  12. Lee, J. (2008)

Sources