Big duck petrel
| Big duck petrel | ||||||||||
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Pachyptila vittata |
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| Systematics | ||||||||||
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| Scientific name | ||||||||||
| Pachyptila vittata | ||||||||||
| ( Forster , 1777) |
The Big Duck Petrel ( Pachyptila vittata ), also Breitschnabel-billed Prion called, is a monotypic nature of the family of petrels (Procellariidae) of its range in the southern Atlantic Ocean , southern Pacific and the southern Indian Ocean has. There is a possibility of confusion with other species of whale birds and the blue petrel .
The IUCN classifies the great duck petrel as harmless ( least concern ). The population is estimated at 15 million sexually mature individuals.
Appearance
When fully grown, the great duck petrels reach a body length of about 29 centimeters and then weigh between 150 and 225 grams. The wing length is 18.1 to 22.5 centimeters and the wingspan is 57 to 66 centimeters.
The sexes are feathered identically. The birds are generally mouse gray and have a darker "M" that goes across both wings. The underside of the body is white-brown. The beak is noticeably wide. With its comb-like plates, it is particularly adapted to fishing for plankton . Similar to the great spotted petrel , they fly foraging in which they repeatedly touch the surface of the water with their feet while at the same time pushing their beak through the water to catch food. The flight is slower and less erratic than that of other whale birds. The great duck petrel also glides more frequently in the air than is observed with the other representatives of this genus.
distribution
The great duck petrel breeds on sub-Antarctic islands mainly south of New Zealand. Breeding sites are found on the coasts of the Foveaux Strait , on small islands in the Stewart Island region , on the Snares Islands and the Chatham Islands . Outside of the breeding season, it can be found over the oceans south of the 30th southern parallel as well as on the west and south coast of Australia and off South Africa.
Way of life
Large duck petrels can usually be seen in schools on the high seas. They mainly eat crustaceans during the summer and small cephalopods during the winter.
They nest on slopes or between stones in self-dug structures. These are usually four feet long. The actual nesting trough is covered with leaves, grass or twigs. The breeding season usually falls between August and September. The clutch consists mainly of a single, white-shelled egg. The breeding season is around fifty days and the time it takes for the young to fledge is similarly long. Both parent birds are equally involved in the breeding and rearing of the young bird. They only raise one clutch per year. On some breeding islands near New Zealand, predators include the Wekaralle as well as introduced cats and rats. On Tristan da Cunha , the reenactment by these predators has led to a sharp decline in breeding birds. In contrast, great duck petrels are still numerous on the predator-free Gough Island .
supporting documents
literature
- Hadoram Shirihai: A Complete Guide to Antarctic Wildlife. The Birds and Marine Mammals of the Antarctic Continent and Southern Ocean . Alula Press, Degerby 2002, ISBN 951-98947-0-5 .
Single receipts
- ^ Shirihai, p. 173.
- ↑ BirdLife Factsheet on the Great Duck Petrel , accessed December 12, 2010
- ↑ a b Shirihai, p. 174.
Web links
- Pachyptila vittata inthe IUCN 2012 Red List of Threatened Species . Listed by: BirdLife International, 2012. Retrieved November 17, 2012.