Kermadec petrel
| Kermadec petrel | ||||||||||
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Kermadec petrels, nestling and adult birds |
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| Systematics | ||||||||||
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| Scientific name | ||||||||||
| Pterodroma neglecta | ||||||||||
| ( Schlegel , 1863) |
The Kermadec petrel ( Pterodroma neglecta ) is a bird art from the family of the petrels . The species is only found in the tropical and subtropical Pacific, where it breeds on small islands. It is named after the Kermadec Islands off the New Zealand coast. Kermadec petrels can be observed all year round over the waters around this archipelago.
The IUCN classifies the Kermadec petrel as not endangered ( least concern ) and estimates the worldwide population at 150,000 to 200,000 sexually mature individuals.
features
The Kermadec petrel reaches a body length of 38 centimeters, the wingspan is 92 centimeters, the average weight is 509 grams. It is a medium to large petrel that does not exhibit sexual dimorphism .
The plumage is individually colored very differently. The pale or light color morph has a predominantly white to gray-white head. The forehead, the top of the head and the nape are speckled gray and brown. The wings are black-brown on the top, while the top of the body is pale ash-brown. The underside of the body is white, and there are often dirty brown spots on the chest. The dark morph, on the other hand, is completely black-brown and has small white spots only on the base of the beak and on the sides of the head. There are numerous intermediate forms between these two extreme morphs. In all morphs, the iris is brown and the beak is black. The legs and feet are whitish-pink. The birds also have a conspicuous white spot on the lower wings that begins at the base of the wing feathers. They can be distinguished from other petrels mainly by this white spot.
The very variable plumage color means that the Kermadec petrel can be confused with several other petrel species. It is particularly similar to the Trinidad petrel , which generally has a dark head and whose lower wings are paler. The rare phoenix petrel has dark underwings and is completely missing the white spot. This also applies to the magenta petrel , the murphy petrel and the long-winged petrel .
Distribution area and way of life
The Kermadec petrel breeds on islands in the South Pacific between the 25th and 35th parallel south. The brood islands include the Kermadec Islands north of New Zealand, the Lord Howe Archipelago in the Tasman Sea and the Juan Fernández Islands off the Chilean coast. The distribution area outside of the breeding season is not exactly known, but it is assumed that the birds occur between the 20th and 35th parallel south. Non-breeding birds occasionally cross the equator and have also been observed at 28 ° North. Kermadec petrels can be seen off the west coast of Mexico, off Peru and Chile, around Hawaii, in Polynesia, occasionally off the east coast of Australia and as a stray visitor in the north of New Zealand. During Hurricane Gracie in the fall of 1959, Kermadec petrels were blown as far as the Lookout Mountain Sanctuary in Pennsylvania . Until then, the bird species had not yet been observed as a random visitor in North America .
Around 1908, around 500,000 birds were still breeding on Raoul Island , an island belonging to the Kermadec Islands, and there are hardly any breeding birds left there due to cats and rats introduced there as well as hunting by humans. On Easter Island they disappeared as breeding birds because of these predators. On the Juan Fernándes Islands, Kermadec petrels are also eaten by cats and coatis.
Way of life
The way of life of the Kermadec petrel is largely unexplored. Up to the end of the 20th century, the most intensive and precise observations of reproductive behavior up to then came from a ten-month stay of two ornithologists on Raoul Island in 1908. Of the food spectrum of this species, only that the stomachs of young birds contained cephalopods and crustaceans. Food is only taken from the surface of the water. On the high seas, Kermadec petrels are mostly observed individually. However, they breed in colonies and are then also associated with other sea birds such as albatrosses. The nest density in such breeding colonies can be very high. On Raoul Island, where Kermadec petrels hardly breed, there were once counted 4,000 nests per hectare. Kermadec petrels only defend the immediate nest environment and both parent birds are involved in the breeding business and feed the young birds. They are ground brooders that hide their nests under vegetation.
supporting documents
literature
- PJ Higgins (Eds.): Handbook of Australian, New Zealand & Antarctic Birds , Volume 1, Ratites to Ducks, Oxford University Press, Oxford 1990, ISBN 0-19-553068-3
Web links
- BirdLife factsheet on the Kermadec petrel
- Pterodroma neglecta inthe IUCN 2013 Red List of Threatened Species . Listed by: BirdLife International, 2012. Retrieved November 7, 2013.
Single receipts
- ↑ BirdLife Factsheet on the Kermadec Petrel , accessed May 28, 2011
- ↑ a b Higgins, p. 436
- ↑ a b Higgins, p. 437
- ↑ Kermadec Petrel in Pennsylvania ( English , PDF; 383 kB) University of New Mexico . Retrieved May 7, 2009.
- ↑ a b Higgins, p. 438