Shagfish
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Sandfish ( Phalacrocorax neglectus ) in breeding plumage |
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| Scientific name | ||||||||||||
| Phalacrocorax neglectus | ||||||||||||
| ( Wahlberg , 1855) |
The shagfish ( Phalacrocorax neglectus ) is a species of bird in the Phalacrocorax family within the cormorant family. The dark brown to black colored species inhabits the West African coast from Namibia to South Africa . It breeds in colonies and feeds primarily on fish and lobster . The IUCN lists the species as " critically endangered " because its breeding grounds are increasingly being destroyed and its prey is overfished.
Appearance
Coastal shags reach a head-trunk length of 76 centimeters and a wingspan of a maximum of 132 centimeters. The weight is a maximum of 1800 grams. There is no gender dimorphism . Adult birds have dark brown to black feathering all over their bodies, their legs are dark gray in color. In contrast to that of many other cormorants, the body looks rather stocky. The beak is relatively short and gray in color. Breeding birds have a conspicuous crest on their foreheads and a patch of white feathers on their rump. This plumage-parts along with the remaining feathers after the breeding blossomed and then only vaguely recognizable. The iris appears bright yellow from a distance, but is more greenish when viewed from close up. Young birds are lighter brown in color than adult birds and are colored white by the stream.
distribution and habitat
Coast shags are common on the west coast of South Africa from Cape Agulhas to southern Namibia in the area of influence of the Benguela Current. The species is purely marine and never occurs inland. It usually stays near the coast and is rarely found more than a few kilometers from the mainland. High stand densities are reached near kelp forests , where the species prefers to forage.
food
The main part of the diet is made up of small fish and invertebrates , especially gobies and lobsters. Like all cormorants, the species prefers to catch its prey by diving by following and catching it while swimming underwater. Coastal shags usually hunt alone, but some animals also hunt together. Since the plumage of the species absorbs water, it must be dried after a dive. Like most cormorants, shags spread their wings and let the sun or wind dry their plumage.
Breeding behavior
The beginning of the breeding season varies depending on the food supply, but is usually in May to July. The species breeds in about 30 small colonies of usually fewer than 100 pairs on small rock islands off the coast. The largest colonies are on Mercury Island and Ichaboe Island off Namibia, where together 80 to 90% of the total population of this species breed. Usually the brood is placed on ledges, but also on breakwaters and other artificial structures. The nest is built from algae , sticks and feathers and glued with feces. It is often used for several years and is constantly being expanded, making it very large and heavy. Usually 2 eggs are laid. After an incubation period of around 30 days, the chicks, which are initially naked, hatch. Black down grows on the body , the down dress is interspersed with white feathers on the head. The youth dress is developed after another 30 days. Usually both young birds fledge.
Migratory behavior
The species is a pronounced resident bird . Even outside the breeding season, adult birds rarely move more than ten kilometers from their breeding site and often return there. Young birds, however, tend to have a pronounced dismigration and then sometimes cover several hundred kilometers until they settle in another colony.
Systematics
As with all cormorants, the exact systematic position of the species is disputed. Some scientists put the species in the monotypic genus " Compsohalieus ", but this view is not generally accepted. No subspecies are distinguished.
Hazard and protection
The IUCN lists the species as " critically endangered " because it breeds in only about 30 colonies and the already small population has decreased from 7,600 breeding pairs in 1980 to 2,600 breeding pairs in 2006 due to overfishing of prey and destruction of breeding grounds by breaking down guano . In the two largest colonies on Mercury Island and Ichaboe Island off Namibia, 80 to 90% of the entire population breed together, which makes the species particularly susceptible to negative influences.
literature
- Josep del Hoyo , Andrew Elliot, Jordi Sargatal : Handbook of the birds of the world. Volume 1: Ostrich to Ducks. Lynx Edicions, Barcelona 1992, ISBN 84-87334-10-5 .
Individual evidence
- ↑ Phalacrocorax neglectus in the endangered Red List species the IUCN 2011. Posted by: BirdLife International, 2010. Accessed November 13, 2011th
