Gray-backed petrel
| Gray-backed petrel | ||||||||||||
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Gray-backed petrel ( Garrodia nereis ) |
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| Systematics | ||||||||||||
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| Scientific name of the genus | ||||||||||||
| Garrodia | ||||||||||||
| Forbes , 1881 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Garrodia nereis | ||||||||||||
| ( Gould , 1841) |
The gray-backed petrel ( Garrodia nereis ) is a species from the family of the southern petrels and the only recent species in its genus Garrodia .
The IUCN classifies the gray-backed petrel as not endangered ( least concern ) because it has a very large distribution area and the population numbers seem to be stable. The worldwide population is estimated by the IUCN at 200,000 sexually mature individuals.
Appearance
The gray-backed petrel reaches a body length of 16 to 19 centimeters. The wing length is 12.4 to 14 centimeters and the wingspan is 39 centimeters. Gray-backed petrels weigh between 21 and 44 grams. Females tend to be slightly larger and heavier than males.
The head and the upper side of the body as well as the wing covers are slate black, the coat and the trunk, however, are somewhat pale gray. The throat and front chest are also dark. The belly, on the other hand, is white. The beak and legs are black. The tail is relatively short and in flight the feet protrude slightly over the tip of the tail. The flight appears fluttering and is reminiscent of the way bats fly. They usually fly very close to the surface of the water.
It can be confused with the frigate storm swallow .
distribution
The gray-backed petrel occurs mainly in the south of the southern hemisphere, where it is circumpolar. The breeding islands include the Falkland Islands , South Georgia, Gough Island , East Crozet Islands , Kerguelen , Auckland Islands , Antipodes, Chatham Islands, and possibly Macquarie Island . The gray-backed petrel also prefers to stay in the region of its breeding colonies outside of the breeding season.
Way of life
The gray-backed petrel lives on barnacles and other crustaceans that are not yet fully grown . The food spectrum occasionally also includes small fish. On the high seas, the gray-backed petrel can usually be seen near floating kelp beds. While foraging it can be observed all year round, both solitary and in small schools. It usually does not follow ships.
The gray-backed petrel breed individually as well as in loose colonies, either in shallow hollows or in short breeding tubes that can be up to 50 centimeters deep. The egg is laid on the bare ground. The brood tubes are usually found between dense tufts of grass or other low-growing vegetation on flat ground or gently sloping slopes. The clutch consists of a single, white-shelled egg with small spots on the wider end. The breeding season is about 45 days. It is not yet known at what age the young birds fledge. Both parent birds are equally involved in the breeding and rearing of the young bird.
In the Falkland Islands, breeding gray-backed petrels are often struck by short-eared owls . It is very likely that, similar to other ground-breeding seabirds, introduced mammals will have an adverse effect on the population. In addition to rats and feral domestic cats, sheep and domestic cattle are likely to have an impact on population numbers as they graze on the tufts of grass between which the petrel breeds. Such grazing domestic animals were removed on two small islands of the Chatham Group, which among other things led to the reintroduction of the gray-backed petrel on these islands.
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
- ↑ BirdLife factsheet on the gray-backed petrel , accessed December 13, 2010
- ^ Shirihai, p. 186
- ^ Shirihai, p. 186
- ^ Shirihai, p. 187
- ^ Shirihai, p. 187
- ↑ Wood, p. 58
- ^ Wood, p. 59
Web link
- Garrodia nereis inthe IUCN Red List of Threatened Species 2013.1. Listed by: BirdLife International, 2012. Retrieved November 9, 2013.