White-chin petrel

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White-chin petrel
Procellaria aequinoctialis in flight.jpg

White-chin petrel ( Procellaria aequinoctialis )

Systematics
Class : Birds (aves)
Order : Tubular noses (Procellariiformes)
Family : Petrels
Genre : Procellaria
Type : White-chin petrel
Scientific name
Procellaria aequinoctialis
Linnaeus , 1758
White-chin petrel soaring
Swimming white-chin petrel

The white-chinned petrel ( Procellaria aequinoctialis ) is a monotypical species from the petrel family. It is a large, powerfully built petrel that occurs in the south of the southern hemisphere. The longline fishery is one of the most threatening factors for this species .

The IUCN classifies the white-chinned petrel as endangered ( vulnerable ), as it assumes that there is currently a sharp decline in the population. On some of the breeding islands, the number of occupied breeding caves fell by 28 percent over a period of twenty years, and in Prydz Bay , Antarctica , the number of white-chin petrels observed fell by 86 percent between 1981 and 1993. Overall, the population is estimated at 3.5 million sexually mature individuals.

Appearance

The white-chin petrel reaches a body length of 51 to 58 centimeters. The wing length is 35.5 to 41.5 centimeters and the wingspan is 134 to 147 centimeters. The weight of the white-chin petrels varies between 1.28 and 1.39 kilograms. Males tend to have slightly longer wings than females and a wider beak.

The white-chin petrel has predominantly black-brown plumage. He only has a small white chin patch, the size of which varies from person to person and which is usually not visible during field observations. The pale yellow beak contrasts strikingly with the dark plumage and is very powerfully built. The feet are black. The hand wings are a little lighter on the underside. The plumage of the young birds hardly differs from that of the adult birds.

There is a possibility of confusion with the Westland petrel , the Parkinson's petrel and the pale-footed shearwater .

distribution

The white-cheeked petrel breeds in the Falkland Islands , South Georgia , Prince Edward Islands , Crozet Islands , Kerguelen, Auckland Islands , Campbell Island, and Antipodes Islands . Outside of the breeding season, it is observed on the coasts of South America up to the 6th southern parallel and in Africa up to the 15th southern parallel. The most important breeding sites are in South Georgia. Only around 1,000 to 5,000 breeding pairs breed on the Falkland Islands.

Way of life

The white-cheeked petrel lives mainly on cephalopods, fish and crustaceans. It occasionally preyes on its food by dive diving from a height of up to 13 meters. Outside of the breeding season, fish play a bigger role in its diet than it does during the breeding season. It can occasionally be seen looking for food individually, but more often it hangs in loose flocks and is then socialized with other seabirds. Occasionally, the white-cheeked petrel also follows ships on its forage.

White-chin petrels breed in loose colonies. They vigorously defend the entrance to their breeding caves. Self-dug earth structures are used for the brood, which are dug on gently sloping hills. The nest tubes are one to two meters long. At the end there is the nest hollow, which is laid out with only a little material.

In the Falkland Islands, white-chin petrels return to breeding colonies in late September. The clutch consists of only one egg, which is laid in the Falkland Islands in late October or early November. The breeding season is 57 to 62 days. The young birds fledge after 87 to 106 days. Only one young bird is raised per year. Both parent birds are equally involved in the breeding and rearing of the young bird.

This large petrel is slightly less threatened by rats introduced to the breeding islands than smaller seabirds that build nesting tubes. However, feral domestic cats can develop into a population-threatening factor in the breeding colonies.

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
  • Robin and Anne Woods: Atlas of Breeding Birds of the Falkland Islands , Anthony Nelson, Shorpshire 1997, ISBN 0904614-60-3

Single receipts

  1. ↑ BirdLife Factsheet on the White-chin Petrel , accessed December 13, 2010
  2. ↑ Shirihai, p. 158 and p. 160
  3. ^ Shirihai, p. 158
  4. ↑ Wood, p. 51
  5. ^ Shirihai, p. 160
  6. ↑ Wood, p. 50

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