Laysan reed warbler
| Laysan reed warbler | ||||||||||||
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Laysan's reed warbler ( Acrocephalus familiaris familiaris ) |
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| Acrocephalus familiaris familiaris | ||||||||||||
| ( Rothschild , 1892) |
The Laysan reed warbler ( Acrocephalus familiaris familiaris ) is an extinct bird belonging to the genus of the reed warbler ( Acrocephalus ). It was endemic to the tiny Hawaiian island of Laysan .
description
The Laysan reed warbler was similar in appearance to the critically endangered Nihoa reed warbler ( Acrocephalus familiaris kingi ). Both breeds are also known as the South Sea Warbler or Hawaiian Warbler ( Acrocephalus familiaris ). The Laysan reed warbler reached a size of ten to thirteen centimeters. The back was gray-brown, the belly brownish white. The wings and tail were darker in color. There were only minor differences in color between the sexes.
Food and way of life
The Laysan reed warbler was an insect eater. Its diet consisted of moths, flies, beetles and caterpillars. Its English name millerbird is derived from its preferred owl butterfly species Agrotis laysanensis , which was colloquially known as miller moth and is also considered extinct . He was a resident .
The ornithologist George Campbell Munro described this bird as very lively and trusting. He preferred to stay in the tall tussock and love grass and even flew into the dwellings to hunt for butterflies.
Reproduction
The Laysan reed warbler was monogamous. The breeding season was from May to June and the young were looked after until early summer. The nest was built in the tall love grass ( Eragrostis ) along a lagoon. The clutch consisted of two to three eggs that were incubated by both parents for 17 days. The chicks were nestled.
die out
As recently as the 1890s, the Laysan reed warbler was a very common bird. In 1903, guano gatherers released rabbits on Laysan, which ate almost all of the vegetation. In the period that followed, the number of birds fell rapidly. While a USCGC Thetis expedition census in April 1915 showed about 1,500 specimens, scientists at Iowa State University observed few individuals in 1911 and during a brief visit in February 1916. In 1923 there was an unconfirmed report by the Tanager expedition, which is, however, doubted by the American paleontologist Storrs Lovejoy Olson . As a result, it can be assumed that the bird died out sometime between 1915 and 1923.
As a result of the destruction of the vegetation on Laysan, the Laysan warbler was exposed to heavy nest looting, in particular by the Schwarzkopf turnstone , the Laysan dresser bird and the bristle curlew . Introduced rodents also ate the eggs and killed the chicks. In addition, by 1911 the moths, which were the main food of the Laysan reed warbler, had disappeared because the rabbits ate their host plants. The only remaining source of food was the Neoscatella sexnotata fly , a saltwater fly that is endemic to Hawaii. Although this fly is quite common on Laysan, the Laysan reed warbler lost the aggressive competition with the Laysan duck , for which this fly species is also the main food. The Laysan Warbler was the first of three land birds endemic to Laysan to be extinct. The Laysan Apapane ( Himatione freethi ) population fell victim to a sandstorm in April 1923 and the Laysan ralle ( Porzana palmeri ) died out in 1944.
literature
- James C. Greenway: Extinct and Vanishing Birds of the World . Dover Publications, New York 1967, ISBN 0-486-21869-4 .
- Errol Fuller: Extinct Birds . 2000, ISBN 0-8160-1833-2 .
- David Day: The Doomsday Book of Animals . Ebury Press, London 1981, ISBN 0-670-27987-0 .
- Edwin Antonius: Lexicon of extinct birds and mammals . Natur und Tier Verlag, Münster 2003, ISBN 3-931587-76-2 .
- Dieter Luther: The extinct birds of the world . Westarp Sciences, 1986, ISBN 3-89432-213-6 .
- Lionel Walter Rothschild: Descriptions of seven new species of birds from the Sandwich Islands . In: Ann. Mag. Nat. Hist. tape 6 , no. 10 , 1892, p. 108-112 .
- Walton Beacham: World Wildlife Fund Guide to Extinct Species of Modern Times . 1997, ISBN 0-933833-40-7 .
Individual evidence
- ^ GD Butler, Jr., RL Usinger: Insects and other invertebrates from Laysan Island. In: Atoll Res. Bull. 98, 1963, pp. 1-30. ( PDF full text ( Memento from June 11, 2011 in the Internet Archive ))
- ^ RB Clapp, Miklos DF Udvardy, AK Kepler: An annotated bibliography of Laysan Island, Northwestern Hawaiian Islands. In: Atoll Res. Bull. 434, 1996, pp. 1-92. PDF full text
- ^ HR Dill, WA Bryan : Report of an Expedition to Laysan Island in 1911. In: US Department of Agriculture, Biological Survey Bulletin. 42, 1912.
- ^ Storrs L. Olson: History and ornithological journals of the Tanager expedition of 1923 to the Northwestern Hawaiian Islands, Johnston and Wake Islands. In: Atoll Res. Bull. 433, 1996, pp. 1-210. PDF full text
Web links
- Acrocephalus familiaris in the endangered Red List species the IUCN 2008. Posted by: BirdLife International, 2008. Accessed January 31 of 2009.
- ARKive - Images and information on the Laysan Reed Warbler