Tristan Albatross

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Tristan Albatross
Tristan Albatross (1) .jpg

Tristan Albatross ( Diomedea dabbenena )

Systematics
Class : Birds (aves)
Order : Tubular noses (Procellariiformes)
Family : Albatrosses (Diomedeidae)
Genre : Diomedea
Type : Tristan Albatross
Scientific name
Diomedea dabbenena
Mathews , 1929

The Tristan albatross ( Diomedea dabbenena ) is an endangered species of bird in the albatross family . Its breeding area is limited to Gough Island in the Tristan da Cunha group of islands in the South Atlantic .

features

The Tristan albatross looks very similar to the wandering albatross and can hardly be distinguished from it in flight. It reaches a size of 110 centimeters and a wingspan of 350 centimeters. The upper wing coverts are darker than those of the wandering albatross. The beak is pink with a lighter tip. The eyes are dark, the legs and feet are pink or gray.

distribution

The main breeding area of ​​the Tristan albatross is restricted to Gough Island. The colony on the island of Tristan da Cunha has expired. Two to three breeding pairs have been observed for inaccessible . Outside the breeding season, the birds hunt distributed in the waters of the South Atlantic between South Africa and Brazil . Evidence of a stray visitor in Australian waters indicates that the migrations of the Tristan albatross also lead across the Indian Ocean .

Way of life

The nesting sites are located above the tree line between 400 and 700 meters above sea level, especially on slopes in damp heathland. Foraging takes place over the open ocean. Albatross couples stay loyal for a lifetime. The reproduction rate is very low; an egg is only laid every two years. The breeding season is between December and February. The fledglings fledge between the following November and February. At the age of four or five, the albatrosses return to the places where they were born. They breed for the first time after six to eight years. The diet consists of fish, octopus and crustaceans. Presumably they also follow the fishing vessels and feed on the waste.

Existence and endangerment

The Tristan Albatross is classified by BirdLife International in the category " critically endangered " . On Inaccessible, the albatrosses were exposed to the stalking of pigs and humans. The pigs have since disappeared, but a new breeding colony has never been able to re-establish itself. On the island of Tristan da Cunha, the Tristan albatross was exterminated by the stalking of humans and rats. The house mouse , which chases chicks and was responsible for a 50 percent decline in Tristan albatrosses in just three years, is considered a threat on Gough Island . House mice came to the Gough Islands with sailors in the 18th or 19th centuries and managed to survive in the inhospitable climate. The mice found on this island can weigh up to forty grams, which is significantly heavier than the 25 grams that house mice normally weigh. Albatross cubs weigh up to ten kilograms, but during their nine-month nestling period they are only tucked away by one parent at the beginning and then later have to stay alone at the nesting site while both parent birds look for food on the high seas. For several months you are unable to evade attacks from house mice either on the fly or continuously. If a single mouse attacks a chick, others are apparently attracted by the smell of blood. They eat their way into the albatross boy's body, creating a large open wound. The chick then either slowly bleeds to death or its vital organs fail.

The main threat comes from longline fishing in Brazilian waters, in whose lines many Tristan albatrosses get caught and perish. BirdLife International makes a rough estimate of the total population between 9,000 and 15,000 specimens. During the breeding season in January 2008, 1764 adult birds were counted, but only 246 chicks that survived to fledgling. In 2010 there were 11,300 copies.

Systematics

The Italian-Argentine ornithologist Roberto Dabbene first mentioned this bird in 1926 under the name Diomedea chionoptera alexanderi . Gregory Mathews used the name alexanderi as early as 1916 for a subspecies of the gray-headed albatross , so he described the Tristan albatross again in 1929 as an independent species and honored Dabbene with the species epithet . In 1936 it was classified by Robert Cushman Murphy as a subspecies of the wandering albatross ( Diomedea exulans ). Since the ornithologists Gary Nunn and Scott Stanley demonstrated on the basis of molecular studies in 1998 that the Tristan albatross is a sister taxon that is genetically different from the wandering albatross, it has been generally recognized as a separate species.

literature

  • Richard J. Cuthbert, Richard A. Phillips, Peter G. Ryan: Separating the Tristan Albatross and the Wandering Albatross Using Morphometric Measurements. In: Waterbirds. 26 (3) 2003, pp. 338-344. (on-line)
  • M. Brooke: Procellariidae. Albatrosses and Petrels Across the World. Oxford University Press, Oxford UK 2004, ISBN 0-19-850125-0 .
  • CJR Robertson, GB Nunn: Towards a new taxonomy for albatrosses. In: G. Robertson, R. Gales (Eds.): Albatross biology and conservation. Surrey Beatty & Sons, Chipping Norton, Australia 1998, ISBN 0-949324-82-5 , pp. 13-19.
  • James McQuilken: The Mists of Time. Spitzbergen.de, Nov. 2012

Web links

Individual evidence

  1. ↑ Dominic Couzens: Rare Birds - Survivors, Evolution Losers and the Lost. Haupt Verlag, Bern 2011, ISBN 978-3-258-07629-4 , p. 6.
  2. ↑ Dominic Couzens: Rare Birds - Survivors, Evolution Losers and the Lost. Haupt Verlag, Bern 2011, ISBN 978-3-258-07629-4 , pp. 60-61.
  3. ↑ Dominic Couzens: Rare Birds - Survivors, Evolution Losers and the Lost. Haupt Verlag, Bern 2011, ISBN 978-3-258-07629-4 , p. 62.
  4. ↑ James McQuilken: The Mists of Time . Ed .: Rolf Stange. 1st edition. Spitzbergen.de, Dassow 2012, ISBN 978-3-937903-15-6 , pp. 137 .
  5. ↑ Roberto Dabbene: Diomedea chionoptera alexanderi (not Thalassogeron chrysostoma alexanderi Mathews, 1916). In: El Hornero. 3, August 1926, p. 338.
  6. ^ Gregory Mathews: New name for Diomedea chionoptera alexanderi Dabbene, preoccupied. In: Bulletin of the British Ornithological Club. 50, October 31, 1929, p. 11.
  7. ^ Robert Cushman Murphy: Oceanic Birds of South America . Vol. I. Macmillan, New York 1936.
  8. ^ GB Nunn, SE Stanley: Body size effects and rates of cytochrome b evolution in tube-nosed seabirds. In: Molecular Biology and Evolution. 15, 1998, pp. 1360-1371. Medline, CSA (PDF, online; 176 kB)
  9. ↑ M. Brooke: Procellariidae. Albatrosses and Petrels Across the World. Oxford University Press, Oxford UK 2004, ISBN 0-19-850125-0 .