Guinea pig
| Guinea pig | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
_at_Monterey_Bay.jpg)
Guinea pig ( Phalacrocorax pelagicus ) in breeding plumage |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Phalacrocorax pelagicus | ||||||||||||
| Pallas , 1811 |
The guinea pigeon ( Phalacrocorax pelagicus ) is a species of bird in the genus Phalacrocorax within the cormorant family. The black colored species inhabits the coasts of the northern Pacific and the North American west coast to Mexico . It breeds in small, loose colonies and feeds primarily on fish and crabs . The IUCN lists the species as " not endangered ".
Appearance
Sea shags reach a head-trunk length of 63 to 76 centimeters and a wingspan of a maximum of 101 centimeters. The weight is between 1474 and 2438 grams. Animals of the southern subspecies P. m. splendens are smaller and lighter than those of the northern subspecies. In addition, the species shows a slight sexual dimorphism , the males are on average slightly larger than the females.
Adult birds have shiny blue-black plumage, legs and feet are dark gray in color. Compared to that of other cormorants, the gray beak is very narrow and smaller than that of the otherwise very similar red-faced pig . From the base of the beak to around the eyes, sea shags have bare, red skin that is intensely colored, especially during the breeding season . Breeding birds also have short crests on their foreheads and necks and some white feathers on their head and neck. They have a white spot on their flanks. After the breeding season , the animals molt these feathers and are then uniformly black in color; the scoops are also less pronounced outside the breeding season. The iris is light blue in color. Young birds are dark brown on the back and neck, and light brown on the belly and throat.
distribution and habitat
The distribution area of the guinea pig stretches from the northern Pacific from Japan and Kamchatka to the Aleutian Islands along the coast of Alaska and down to California . Particularly high stand densities are achieved in the area of kelp forests . The species lives marine and mainly colonizes coastal sections with shallow water, estuaries and bays, but avoids the inland. It is less common in areas with deeper water.
food
The main components of the diet are small fish and crabs . Sea shags prefer waters with rocky bottom and kelp forests for hunting. Like all cormorants, the species prefers to catch its prey by diving by following and catching it while swimming underwater. Although it rarely hunts schooling fish , the species occasionally acts opportunistically , following seabirds as they disperse a school of fish. Since the plumage of the guinea pig absorbs water, it has to be dried after a dive. Like most cormorants, the species spreads its wings and lets the sun or wind dry its plumage.
Breeding behavior
The breeding season begins between May and June; the southern population begins breeding earlier due to the more favorable climatic conditions. The species breeds in small, loose colonies, often together with other sea bird species. Preferred nesting sites are cliffs and ledges on which a nest made of algae , grass and sticks is built. This is padded with feathers and solidified with excrement. Since a nest is used anew every year and is constantly being expanded, it can reach a height of several meters. As a rule, three to four eggs are laid, from which naked chicks hatch after an incubation period of around 30 days. Black down grows after a few days before the youth dress grows. On average, three young birds in a brood fledge; in years with good food availability, all young birds often survive.
Migratory behavior
The southern subspecies is a resident bird , only after the breeding season there is dismigration of young birds. The northern Pacific population migrates south to Korea in winter . Individual birds have already been spotted off Hawaii . However, these are considered exceptional cases.
Systematics
As with all cormorants, the exact systematic position of the species and the number of its subspecies is disputed. Some scientists place the species in the genus Stictocarbo , but this view is not widely accepted. There are usually two subspecies:
- Phalacrocorax pelagicus pelagicus : Northern Pacific
- Phalacrocorax pelagicus resplendens : British Columbia to northwestern Mexico
Hazard and protection
The IUCN leads the kind as " not endangered (least concern) ". The species has a wide range and suffers less than other seabirds from overfishing for schooling fish such as sardines and herring . The numerous colonies are often in poorly developed and inhospitable areas and therefore do not threaten to be destroyed by human influence.
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
- ↑ urile pelagicus in the endangered Red List species the IUCN 2010. Posted by: BirdLife International, 2009. Accessed March 13, 2011th
