Pittscharbe
| Pittscharbe | ||||||||||||
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On the right in the foreground of the picture a pittish pod, behind it on the left a potted pod |
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| Scientific name | ||||||||||||
| Phalacrocorax featherstoni | ||||||||||||
| Buller , 1873 |
The pittscharbe ( Phalacrocorax featherstoni ) is a species of bird from the family of cormorants (Phalacrocoracidae). The species occurs exclusively on the Chatham Islands and mainly eats small fish and crustaceans. The Pitt Shag is by the IUCN as endangered ( endangered classified), since the very small stock has continued to decline in recent years. When the breeding pairs were counted during the 1997/1998 breeding season, 729 breeding pairs were counted in the entire breeding area, whereas in 2003/2004 only 547 breeding pairs were breeding. The total population including non-breeding animals is estimated at 1,400 individuals.
Appearance
The pittscharbe is a small, slender cormorant with long, slender wings and a short tail. The body length is about 63 centimeters, the weight about one kilogram. There is no noticeable sexual dimorphism .
In the magnificent dress, the head, the back neck and the upper front neck are blue-black. There is a spring hood on the forehead and back of the head. The pittscharbe has long, white thread feathers ( filoplumae ) on the neck, which can also be found in other places on the head and neck. The upper body is dark olive-brown with a greenish tinge. The individual feathers each have a black point at their tip. The control springs are black. The lower neck and lower body are gray, while the under tail-coverts are black. The long and slender beak is black with a light brown tip. The featherless skin of the face in front of and around the eye is bright grass green. The throat pouch, on the other hand, is black and has blue-green warts. The iris is dark red-brown, the legs and feet are orange. In the plain dress, the hoods are smaller, the white thread feathers on the back of the neck are missing and the throat pouch is green.
Young birds are dark black-brown with a greenish tinge on the head, neck and on the upper side of the body. The chest and stomach are paler brown. The beak is still gray-brown. The featherless skin of the face, legs and feet are yellow and turn orange with age. The iris is gray-brown.
Possible confusion
Several other species of cormorant are found in the Chatham Islands, with which the pittshar can be confused. The cormorant, which is also widespread in Eurasia, is, like the chatham shear, larger and more powerful. From the spotted shag the Pitt Shag distinguished by the darker plumage, the spotted shag has run in breeding plumage also two striking white stripes of the eyes to the shoulders. Fledglings of the pittish shag can be confused with not yet sexually mature black shots, because the fledglings of both species are about the same size, have a slender beak and black-brown plumage. They can be told apart by the color of the feet, as shags have black feet. The pittscharbe also has a shorter tail.
distribution and habitat
The Pittscharbe is endemic to the Chatham Islands, an archipelago belonging to New Zealand , which lies around 800 km east of the main islands in the South Pacific . Pitt shags breed on Chatham Island , Pitt Island , Mangere Island , South East Island , Star Keys , The Pyramid , The Sisters , Murumurus, The Castle and Rabbit Islands .
Pittshars forage for food up to 15 miles off the coast of the Chatham Islands. They are resident birds that have not yet been observed off the Chatham Islands even as wanderers .
Reproductive biology
So far, very little is known about the reproductive biology of the Pittshark. The breeding season falls between August and December. The egg-laying begins in August and the young birds fly out in December. However, young birds were also observed which were still being fed by the parent birds towards the end of January.
The Pittscharbe is a colony breeder that breeds on cliffs and ledges. The immediate nesting area is defended, although only the male pursues conspecifics to the boundaries of the territory. The choice of the nest location is generally made by the male; the female builds the nest from material that the male brings. Ice flowers , grass and other plant material are used, and the nest continues to be built during both the breeding and nestling periods. Old nests are occasionally used again and then supplemented and repaired by the female with new nesting material.
The clutch usually consists of three eggs. These are elliptical, have a rough surface and are light blue in color. No information is available about the duration of the breeding and nestling season.
Threat and Safeguards
The effect of introduced animal species on the breeding success of the pittscharrows is not exactly known, since pittscharrows generally breed in inaccessible places. Some nests or nest, however, were by domestic cattle, feral cats, pigs, dogs and black rats and brown rats and Wekarallen destroyed. About forty to eighty pitties also drown in lobster traps every year. The decline in the population is largely explained by the fact that they can no longer find enough food in the waters around the Chatham Islands.
As a protective measure for this endangered species, the keeping of domestic sheep and cattle on the South East Island was ended as early as 1961. Domestic sheep have not grazed on Mangere Island since 1968. The extermination of feral domestic cats and wekarall on Pitt Island is being considered as further protective measures. As an alternative or in addition, grazing on both Chatham Island and Pitt Island should be restricted in places that are suitable as locations for a breeding colony.
supporting documents
literature
- PJ Higgins (Ed.): Handbook of Australian, New Zealand & Antarctic Birds , Volume 1, Ratites to Ducks, Oxford University Press, Oxford 1990, ISBN 0195530683
Web links
Single receipts
- ↑ BirdLife Factsheet on the Pittscharbe , accessed May 12, 2011
- ^ Higgins, p. 844
- ^ Higgins, p. 844
- ↑ BirdLife Factsheet on the Pittscharbe , accessed May 12, 2011
- ^ Higgins, p. 844
- ^ Higgins, p. 846
- ^ Higgins, p. 845
- ^ Higgins, p. 846
- ↑ BirdLife Factsheet on the Pittscharbe , accessed May 12, 2011