Black-footed albatross
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Black-footed albatross ( Phoebastria nigripes ) |
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| Phoebastria nigripes | ||||||||||
| ( Audubon , 1839) |
The black-footed albatross ( Phoebastria nigripes ) is one of the three species of albatross that live in the North Pacific . With a wing span between 2 and 2.1 meters, it is larger than a Laysanal albatross , but smaller than the very rare short-tailed albatross , both of which are also found in the North Pacific. The black-footed albatross differs from short-tailed albatrosses in juvenile plumage by its dark beak and legs.
Like all albatrosses, the black-footed albatross is a good glider that can swim well. In weak winds, however, wing beats can be observed more often than in other albatross species. He is a very trusting bird who often follows ships.
The IUCN classifies the black-footed albatross as endangered ( vulnerable ). The population is estimated at around 65,000 breeding pairs.
features
Including the black have neither gender or seasonal dimorphism on. The plumage is predominantly dark. The upper sides of the body and wings are black-brown. The underside of the body and the head are gray. There is a narrow white band around the base of the beak. There is a narrow white stripe below the eye. The upper and lower tail coverts are white. The tail and feet are black. The wing length of adult black-footed albatrosses is around 46 to 55 centimeters. The beak is between 13 and 16 centimeters long. The legs measure eleven centimeters. They weigh between 2.2 and 4.1 kilograms.
Nestlings are brown-black with a blackish beak and legs. Young birds are a little darker than adult black-footed albatrosses and have a brown-gray beak.
Occurrence
The bird breeds on Laysan , the Midway Islands , the Japanese Ogasawara and Senkaku Islands, and on the island of Torishima . Formerly there were also breeding occurrences on one of the Bonin Islands , the Johnston Atoll , Wake , the Marcus Island , Iwojima and Taongi, among others . The local loyalty towards the breeding colony is very pronounced. Individual birds rarely change their breeding island. Breeding birds arrive at the breeding site towards the end of October or beginning of November.
The migratory area of the black-footed albatross spans the entire North Pacific, although it mainly resides over the open sea and is rare in coastal waters. Year-round it is more common in the east of the North Pacific. In the winter half-year the occurrence is concentrated in a region around the Hawaiian Islands to the Pacific coast of the USA. In spring, its range extends further north and northwest. As early as May, it can be seen more frequently off the coast of Alaska and near the Aleutians. In summer and early autumn he also reaches the Okhotsk Sea and the Bering Sea on his hikes .
food
Black-footed albatrosses eat cephalopods , crustaceans and tunicates. They look for food day and night. Foraging is especially more effective during the night than during the day, as cephalopods gather in surface water at night. Birds that accompany ships and eat the waste thrown overboard are very active during the day.
The food is only consumed by swimming, while black-footed albatrosses occasionally dip their heads under water. However, you are unable to dive.
Reproduction
Black-footed albatrosses enter into lifelong partnerships. They usually become sexually mature at the age of seven. Black-footed albatrosses not yet sexually mature start visiting breeding colonies during the breeding season at the age of three. In general, only two thirds of the sexually mature population breed. They only lay a single egg.
The breeding colonies are generally located on the breeding islands in the bank area. Typical locations for the breeding grounds are sandy beaches. The nest is a simple depression in the sand. The brood is preceded by courtship dances consisting of ritualized poses and movements. Essential elements of courtship are beak contact with the partner bird, viewing the partner's chest and simultaneous lifting of both wings.
The egg is deposited 18 to 21 days after the birds have arrived in the breeding colony. So the egg-laying falls in November. The egg is elongated ellipsoid, the shell is whitish. Both parents are involved in the brood, the male has the slightly higher brood share. The breeding season is between 63 and 68 days. The first three to four days after being laid the female incubates, then it is replaced by the male, who sits on the egg for an average of 18 days before the female returns to the nest for the first time. In total, the two parent birds separate eight times during the breeding season.
The chick hatches from mid-January to early February. During the first two weeks of life, the young bird is fed daily, then only every other day and immediately before fledging with an interval of three days. The nestling period lasts an average of 140 days. The young birds leave the breeding colony in June.
Duration
The bird is endangered by long-line fishing. It is estimated that between 4,000 and 8,000 birds die each year. Another danger is swallowing floating plastics, which reduces the stomach space for food that is brought to the chick. All breeding sites on US territory are protected. In 2010 the inventory was 120,000 copies. This makes it one of the more common albatross species, but the population is also shrinking here.
supporting documents
literature
- VD Il'ičev, VE Flint (ed.): Handbook of Birds of the Soviet Union. Volume 1: History of exploration, Gaviiformes, Podicipediformes, Procellariiformes . Aula Verlag, Wiesbaden 1985, ISBN 3-89104-414-3 .
- J. McQuilken, R. Stange (Ed.): The fog of time. Spitzbergen.de-Verlag, 2012, ISBN 978-3-937903-15-6 .
Web links
- Phoebastria nigripes in the endangered Red List species the IUCN 2008. Posted by: BirdLife International, 2008. Accessed January 31 of 2009.
Single receipts
- ↑ Il'ičev & Flint: Handbook of Birds of the Soviet Union. Volume 1: History of exploration, Gaviiformes, Podicipediformes, Procellariiformes . 1985, p. 295.
- ^ IUCN website on Black Footed Albatross, accessed June 29, 2013
- ↑ Il'ičev & Flint: Handbook of Birds of the Soviet Union. Volume 1: History of exploration, Gaviiformes, Podicipediformes, Procellariiformes . 1985, p. 295.
- ↑ Il'ičev & Flint: Handbook of Birds of the Soviet Union. Volume 1: History of exploration, Gaviiformes, Podicipediformes, Procellariiformes . 1985, p. 296.
- ↑ Il'ičev & Flint: Handbook of Birds of the Soviet Union. Volume 1: History of exploration, Gaviiformes, Podicipediformes, Procellariiformes . 1985, p. 296.
- ↑ Il'ičev & Flint: Handbook of Birds of the Soviet Union. Volume 1: History of exploration, Gaviiformes, Podicipediformes, Procellariiformes . 1985, p. 297.
- ↑ Il'ičev & Flint: Handbook of Birds of the Soviet Union. Volume 1: History of exploration, Gaviiformes, Podicipediformes, Procellariiformes . 1985, p. 297.
- ↑ Il'ičev & Flint: Handbook of Birds of the Soviet Union. Volume 1: History of exploration, Gaviiformes, Podicipediformes, Procellariiformes . 1985, p. 297.
- ↑ Il'ičev & Flint: Handbook of Birds of the Soviet Union. Volume 1: History of exploration, Gaviiformes, Podicipediformes, Procellariiformes . 1985, p. 297.
- ↑ James McQuilken: The Mists of Time . Ed .: Rolf Stange. 1st edition. Spitzbergen.de, Dassow 2012, ISBN 978-3-937903-15-6 , pp. 137 .