Tristan Albatross

Tristan Albatross
Conservation status
Critically Endangered (IUCN 3.1)[1]
Scientific classification
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] Diomedea chionoptera

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 Diomedeidae family and come from the Procellariiformes order, along with Shearwaters, Fulmars, 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. Finally, they 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, 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 superspecies.^[6] This may be due to it díverging 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] Jeff Clements has not yet,^[8] and the SACC has a proposal on the table to split it.^[9]

Etymology

Diomedea antipodensis breaks into Diomedea referring to Diomedes, whose companions turned to birds.^[10]

Description

It is, however, practically indistinguishable from the Wandering Albatross at sea; the Tristan Albatross is smaller and has a slightly darker back. The Tristan Albatross is 110 cm (43 in) and has a wingspan of up to 3.5 m (11 ft).^[11] The Tristan Albatross also never attains the full white plumage of the Wandering Albatross, and its bill is about 25 mm (0.98 in) shorter.^[7]

Behavior

The Tristan Albatross feeds on fish and cephalopods.

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

Range and habitat

Due to the difficulty in distinguishing them from Wandering 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. They have been sightings near Brazil and also off the coast of Australia.^[7]

The 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.

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.^[12] 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.^[7]

Formerly classified as an endangered species by the IUCN,^[13] 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]

Footnotes

1. ^ ^{a b} BirdLife International (2008)
2. ^ ^{a b} BirdLife International (2008)(b)
3. ^ Robertson, C. J. R. & Nunn, G. B. (1998)
4. ^ ^{a b} Double, M. C. (2003)
5. ^ Burg & Croxall (2004)
6. ^ Brooke, M. (2004)
7. ^ ^{a b c d e f} BirdLife International (2008)(a)
8. ^ Clements, J. (2007)
9. ^ Remsen Jr., J. V. (2009)
10. ^ Gotch, A. F. (1995)
11. ^ http://www.arkive.org/species/GES/birds/Diomedea_dabbenena/more_info.html?
12. ^ Wanless, R. M. et al., (07 Jun 2007)
13. ^ Lee, J. (2008)

References

• BirdLife International (2008). Diomedea dabbenena. In: IUCN 2008. IUCN Red List of Threatened Species. Downloaded on 18 Feb 2009.
• BirdLife International (2008(a)). "Tristan Albatross - BirdLife Species Factsheet". Data Zone. http://www.birdlife.org/datazone/species/index.html?action=SpcHTMDetails.asp&sid=30013&m=1. Retrieved 18 Feb 2009. 
• "The BirdLife checklist of the birds of the world, with conservation status and taxonomic sources." (xls). 2008(b). http://www.birdlife.org/datazone/species/downloads/BirdLife_Checklist_Version_1.zip. Retrieved 18 Feb 2009. ^{[dead link]}
• Brooke, M. (2004). "Procellariidae". Albatrosses and Petrels Across the World. Oxford University Press, Oxford, UK. ISBN 0-19-850125-0. 
• Burg, T.M. & Croxall, J.P. (2004): Global population structure and taxonomy of the wandering albatross species complex. Molecular Ecology 13: 2345-2355.doi:10.1111/j.1365-294X.2004.02232.x PMID 15245406
• Clements, James (2007). The Clements Checklist of the Birds of the World (6 ed.). Ithaca, NY: Cornell University Press. ISBN 978 0 8014 4501 9. 
• Double, M. C. (2003). "Albatrosses (Diomedeidae)". In Hutchins, Michael; Jackson, Jerome A.; Bock, Walter J. et al.. Grzimek's Animal Life Encyclopedia. 8 Birds I Tinamous and Ratites to Hoatzins. Joseph E. Trumpey, Chief Scientific Illustrator (2 ed.). Farmington Hills, MI: Gale Group. pp. 113–116. ISBN 0 7876 5784 0. 
• Gotch, A. F. (1995) [1979]. "Albatrosses, Fulmars, Shearwaters, and Petrels". Latin Names Explained A Guide to the Scientific Classifications of Reptiles, Birds & Mammals. New York, NY: Facts on File. p. 190. ISBN 0 8160 3377 3. 
• Lee, James (06 Oct 2008). "Table 7: Species changing IUCN Red List Status" (pdf). IUCN RedList. BirdLife International. http://www.iucnredlist.org/documents/2008RL_stats_table_7_v1223294385.pdf. Retrieved 18 Feb 2009. ^{[dead link]}
• Remsen Jr., J. V.; et al. (07 Aug 2008). "Proposal (388) to South American Classification Committee: Split Diomedea exulans into four species". South American Classification Committee. American Ornithologists' Union. http://www.museum.lsu.edu/~Remsen/SACCprop388.html. Retrieved 18 Feb 2009. 
• Robertson, C. J. R.; Nunn, G. B. (1998) "Towards a new taxonomy of albatrosses" Albatross Biology and Conservation Chipping Norton, Australia: Surrey Beatty & Sons Ltd. pp. 13–19 
• Wanless, Ross M.; Angel, Andrea; Cuthbert, Richard J.; Hilton, Geoff M.; Ryan, Peter G. (7 June 2007). "Can predation by invasive mice drive seabird extinctions?". Biology Letters 3 (3): 241–244. doi:10.1098/rsbl.2007.0120. ISSN 1744-9561. PMC 2464706. PMID 17412667. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2464706. Retrieved 18 Feb 2009. 

External links

• BirdLife Species Factsheet.