Schwarzscharbe
| Schwarzscharbe | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
Black Sharp ( Phalacrocorax sulcirostris ) |
||||||||||
| Systematics | ||||||||||
|
||||||||||
| Scientific name | ||||||||||
| Phalacrocorax sulcirostris | ||||||||||
| ( Brandt , 1837) |
The black shag ( Phalacrocorax sulcirostris ) is a species of seabird in the cormorant family . The distribution area of the black shark is Australasia.
The IUCN classifies the black pot as not endangered ( least concern ).
Appearance
The black shag reaches a body length of 55 to 65 centimeters, about half of which is accounted for by the body. The wingspan is 95 to 105 centimeters. Black shags weigh between 520 and 1210 grams. There is no noticeable sexual dimorphism .
Shags are slender, uniformly dark-feathered cormorants with a very thin beak and a long tail. The featherless skin of the face is also dark. The plumage is occasionally very shiny, which makes it look very scaly. A thin, not very noticeable brownish, gray or white line runs along the throat. During courtship they have white feathers above the eye. Individual white feathers can also be found on the sides of the head and in the neck. These white feathers are already lost during the breeding season, the then already worn plumage appears dull and brown-black. The iris is bright green. Small, blue-green warts run around the eye. The legs and feet are black.
Young birds are similar to adult birds, but appear a little more brownish overall. In the first year of life, their irises are brownish.
Typical behaviors
Black shags are very sociable birds that can be seen regularly in larger flocks on inland and coastal waters. They rest and breed in trees and bushes in the immediate vicinity of the water. On land they move with a goose-like waddle. The flight is vigorous, phases with strong wing flapping alternate with gliding phases. During the flight, the head and neck are straight, the head is slightly higher or level with the axis of the body. While searching for food in bays, black shags often swim in a line towards the shore in order to catch fish that are swimming with the ebb tide towards the open sea. Shags that are at the rear of such a line often fly up to land in front of the line and dive for fish. They are often socialized with other cormorants and sea birds on land.
Possible confusion
There are three other species of cormorant in the distribution area of the black shark, which are also predominantly dark in color. The cormorant, which is also native to Eurasia, is much larger and more powerfully built. It also has a stronger beak, the featherless skin of the face is yellowish, and in its splendid dress the cormorant has a white spot at the base of the thigh. The white-throated color morph of the Australian dwarf shark has a short, strong yellowish beak. Adult Australian dwarf shags are pinnate white on the lower half of the face and on the throat. However, young birds of this species of cormorant have completely dark plumage. The bronze-colored morph of the Stewart shear is significantly larger than the black shear and is more powerfully built. This species also differs in its significantly thicker neck.
distribution and habitat
The distribution area of the black pigtail is Australia, Tasmania, New Zealand, Indonesia and New Guinea. As a stray visitor, the Schwarzscharbe occasionally also reaches New Caledonia , Lord Howe Island and the Norfolk Island .
In Australia, the black pigtail lives on smaller rivers or lakes with the exception of the deserts in the south of the Northern Territory , in the west of South Australia and in central Western Australia . It also only colonizes existing bodies of water in the arid regions for a short time. In New Zealand, the main distribution area lies on the North Island. While in Australia the black shit occurs most frequently in inland waters, in Tasmania it can be seen mainly in estuaries and brackish water. While foraging, it mainly uses waters with a depth of more than one meter. During the breeding season, the black pigtail is mostly found in swamps and lakes, the shoreline of which is densely overgrown. As nesting trees, they prefer those that are secluded and well protected in the middle of flood plains.
Way of life
Black shags mainly eat fish and prefer smelts , perches and carp. They also eat crustaceans that live in fresh water. Fish is mainly hunted while diving, with black shags preferring to use waters one to two meters deep. Fish are usually impaled with the tip of their beak, with shags aiming at a point behind the gills. Black shags do not eat the caught fish until they have surfaced. the fish is swallowed head first. A common hunt is typical for black shag, where groups hunted together can comprise between 16 and 1,150 individuals. When hunting together, they also catch fish that fish out of the water before their pursuers. Hunting groups usually move slowly, birds swimming farther back regularly fly up and take the lead. It was observed that after finding schools of fish, the black shags swimming in the front line initially swim around them and wait until the other members of a group hunting together have swam up to start the hunt. Black shags are commonly seen as sight hunters, but they have also been observed successfully catching fish in waters with a visibility of less than ten centimeters. The search for food takes place exclusively during the day.
Reproduction
The reproductive biology of the black shit has so far only been investigated superficially. In general, black shags breed in breeding colonies. They are often associated with other species of cormorants, herons, spoonbills and ibises. Single breeding pairs also occasionally occur.
The time of reproduction has not yet been clearly determined. In the north of Australia they generally breed from summer to autumn, but from spring to summer in the south of Australia. However, broods can also occur all year round, if suitable waters as well as sufficient food and nesting opportunities are available. The nest is usually built in trees and can be up to 30 meters above the ground or the surface of the water. In general, they prefer to build their nests in high places. Insufficient data are available for the nest size; one nest examined had a diameter of 30 centimeters and was between 30 and 60 centimeters thick. The clutch generally consists of four eggs. These are elongated oval, have a rough surface or are bluish or greenish white. The breeding season is not known. The young are initially naked after hatching. Older nestlings have black down plumage and the top of the head is feathered the longest. The iris is brown. There are no data available for the duration of the nestling period, the respective proportion of the parent birds in brood care or the development of the young birds. All that is known is that when threatened, nestlings often jump into the water to seek shelter there.
Crows and the wedge-tailed harlequin often eat the eggs of the black peel.
literature
- Simpson & Day: Field Guide to the Birds of Australia . Christopher Helm Publishers Ltd, 1989, ISBN 0-7470-3023-5
- 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
- Videos, photos and sound recordings of Phalacrocorax sulcirostris in the Internet Bird Collection
- Phalacrocorax sulcirostris inthe IUCN Red List of Threatened Species 2013.1. Listed by: BirdLife International, 2012. Retrieved October 6, 2013.