Yellow cup
| Yellow cup | ||||||||||
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Yellowcap ( Fratercula cirrhata ) |
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| Systematics | ||||||||||
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| Scientific name | ||||||||||
| Fratercula cirrhata | ||||||||||
| ( Pallas , 1769) |
The Tufted Puffin ( Fratercula cirrhata ) is a medium-sized bird of the family of the Auks . It occurs exclusively in the North Pacific. No subspecies are recognized.
Appearance
The yellow cap reaches a body length of 40 centimeters and weighs about 780 grams. It is therefore a large, strongly built alken bird. The beak is large, narrow and very high. The plumage is dark, apart from the white face and the yellow headdress. Its flight seems rather clumsy, due to the relatively small wings it is not very agile in the air and needs sloping surfaces on land and a longer run-up before it can take off at sea. On land it moves in a rolling gear. Resting birds have an upright posture.
In the splendid dress, the plumage on the upper side of the body is black-brown, the underside is dark brown. The face is white. At the back of the head there are shiny yellow feathers that can reach a length of seven centimeters. The under wing-coverts are gray-brown. The iris is gray-white with a very thin, featherless red eye ring. Two thirds of the bill are red, during the breeding season it has a large olive-green to yellowish horn plate at the base of the beak. There are three vertical notches at the tip of the beak. The feet and legs are red to orange-red. Not yet sexually mature birds at the age of two years are already very similar to breeding birds, but their beak is smaller and paler. They usually only have two beak notches. The elongated facial feathers are shorter and more whitish than golden yellow.
In the plain dress , the yellow cap is completely black-brown on the upper side of the body and dark brown on the underside of the body. There are only a few paler spots on the stomach and a gray-brown spot behind the eye. The elongated feathers at the back of the head are missing, as is the olive-green to yellowish horn plate on the beak. The beak is dull red at the tip and turns brown towards the base of the beak. Fledglings resemble adult birds in their simple dress. With them, however, the throat and upper chest are gray-brown. The underbust and the belly are white with brown spots. The iris is brown-gray, the bare skin around the eyes is black. The beak is brown, triangular and significantly smaller than that of the adult birds.
Distribution area
The yellow cap is a bird of the boreal and arctic waters of the North Pacific. Its distribution area extends from Big Sur on the California coast to Hokkaidō . However, it occurs in large numbers only in the region from British Columbia to the Sea of Okhotsk . Single yellow caplets are occasionally observed in the Chukchi Sea and penetrate as far as Wrangel Island . Stray visitors can occasionally be seen in the Beaufort Sea .
Breeding colonies are particularly numerous on islands off the Alaska Peninsula , the Aleutian Islands and the Kuriles, and in the Sea of Okhotsk. There are fewer breeding colonies in the Bering Sea and marginal populations also breed on the islands of the Chukchi Sea and Wrangel Island. The main distribution area are the eastern Aleutian Islands, especially the islands that lie at the transitions between the Bering Sea and the Pacific. Of the 58 islands with a breeding population of more than 10,000 breeding yellow-capped lobsters, nine are in the area between Akutan Island and Unalaska and another nine between Unimak Island and Akutan Island. The southernmost breeding colonies are found on the Asian coast on Hokkaidō.
The wintering areas of the yellow coppers are not exactly known. They generally stay in the open sea. Exceptions are some yellow caplets, which remain in the region of their breeding colonies, provided that the icing does not force them to move further south. During the winter, yellow pancakes are observed off the coast of California, in the north of the Sea of Japan and from north Honshu to the east coast of Japan. Off the coast of British Columbia, on the other hand, yellow caplets are rarely seen during the winter months.
food
Yellow poppies look for their food far off the coast all year round. They also often stay away from the continental shelves . There, where the yellow caplet and the hornlund share the breeding colonies, yellow cappels look for food further away from the breeding colony.
Fledglings are fed almost exclusively with fish by their parent birds. The diet of adult birds consists at least partially, if not largely, of zooplankton. They also occasionally eat crabs and other small marine animals.
Reproduction
Like most seabirds, yellow caplets are colony breeders. They return to their breeding colonies between March and May. In the Farallon Islands , the first yellow caplets are usually seen between April 12th and April 6th. They arrive on the commander's islands towards the end of April and on the Chukchi peninsula between late May and early June.
Yellow-coppers usually breed on islands with steep grass slopes and floors that are suitable for digging nest holes. They also use overgrown scree slopes and, as an exception, breed on cliffs. On islands where foxes are also found, they only breed on inaccessible cliffs. In some parts of the Alaskan coast, yellow scouts dig their burrows in sand dunes that are no higher than two meters. In contrast, the Barren Islands have breeding caves more than 600 meters above sea level. On the Farallon Islands, yellow- capped lions occasionally displace rhinoceros and pigeon ducks from their nesting holes. The nesting density on Talan Island in the Sea of Okhotsk is between 0.3 and 0.9 caves per square meter.
The nest is usually in earthworks, occasionally in crevices or in caves under boulders. Earthworks are dug by the yellow poppet with beak and feet. The entrance of a typical breeding cave has a diameter of 15 centimeters and can be up to two meters long. The eggs are laid between the end of April and the end of May. The clutch consists of only one egg. The egg is white with occasional pale brown or bluish spots or scratches on the eggs. The egg is incubated by both parent birds. The breeding season averages 45 days.
The young birds are fed an average of 3.5 times a day by the parent birds. The parent birds usually bring in food in the early morning hours. Occasionally young birds are also fed in the late afternoon hours. The amount of food that the parent birds bring in each day varies between 14 and 22 grams. In some breeding colonies, kleptoparasitism by Bering gulls occurs .
The growth of the young birds depends on the amount of food that the parent birds can bring. Immediately after hatching, they weigh an average of 69.4 grams and reach their maximum weight on the 35th day of life. The weight of the fledglings at the time of flight varies considerably. In the Gulf of Alaska, the young birds fly out weighing between 274 and 609 grams.
Duration
Between 800,000 and 1,000,000 breeding birds live in the area between Akutan Island and Unimak Island. There is also the largest colony of this species on Egg Island with 163,000 breeding birds. The larger colonies include those on Forrester Island off the southeastern coast of Alaska (70,000 breeding birds), on Castle Rock in the Shumagin Islands (80,000 breeding birds), Amagat Island (100,000 Breeding birds) off the Alaska Peninsula and on Amatuli Island in the Gulf of Alaska (93,000 breeding birds). The only notable colony off the coast of British Columbia is on Triangle Island (50,000 breeding birds). Otherwise there are no breeding colonies south of Alaska with more than 10,000 breeding pairs. Small colonies can be found off the coast of Washington and Oregon. In the 19th century, yellow scaly pods were still breeding on the Californian Channel Islands , but in the 20th century there were no more breeding colonies here. On the Farallon Islands, California's most important colony, there were still thousands of breeding pairs in the 19th century, but in 1982 the population was only 100 breeding birds. Only a few pairs breed on Wrangel Island and in the Russian Bering Sea. The largest Asian colony is on the Commander Island with more than 20,000 breeding birds and 80,000 breeding birds on Talan Island. On Hokkaidō, the stocks have declined sharply. The causes of the population decline on various breeding islands are drowning in fishing nets, introduced predators and human disturbances.
supporting documents
literature
- Jonathan Alderfer (Ed.): National Geographic complete Birds of Northamerica. National Geographic, Washington DC 2006, ISBN 0-7922-4175-4 .
- Anthony J. Gaston, Ian L. Jones: The Auks (= Bird Families of the World. Vol. 4 (recte 5)). Oxford University Press, Oxford et al. 1998, ISBN 0-19-854032-9 .
Single receipts
- ↑ a b Gaston et al., P. 298
- ↑ a b c Gaston et al., P. 299
- ↑ a b c Gaston et al., P. 301
- ↑ Gaston et al., P. 302
- ↑ Gaston et al., P. 303
Web links
- Fratercula cirrhata in the endangered Red List species the IUCN 2008. Posted by: BirdLife International, 2008. Accessed on January 1 of 2009.
- Videos, photos and sound recordings of Fratercula cirrhata in the Internet Bird Collection