Pigeon Guillemot

Taubenteiste ( Cepphus columba )

The Taubenteiste ( Cepphus columba ) is a medium- sized species of the family of the Auks, whose distribution area is the northern part of the Pacific. It is very similar to the other species of the genus Cepphus, especially the Atlantic guillemot, which is somewhat larger. In their area of ​​distribution is the Taubenteiste due to the white wing patches and bright red feet one of the easiest to identifying seabirds.

There are five subspecies described for this species, which differ significantly in body size and weight to some extent.

Appearance

Taubenteisten vary significantly according to their geographical distribution to significant differences in body size and weight. The average weight varies 417-524 grams, with the subspecies C. c. snowi the lightest and C. c. kaiurka is the heaviest subspecies. The wing length varies from 17.9 to 19.7 inches.

Adult birds have a black-brown plumage with a distinctive white patch on the wings. The dark beak is thin and the legs and feet are red. In winter, the top is gray black and the bottom white. Taubenteisten can run well and have to land an upright position. The beak is long and slender, the upper and lower mandible are formed almost symmetrical and dagger- like. The iris contrasts barely over dark plumage, in some individuals, however, a bright eye-ring is visible.

Distribution area

The Taubenteiste breeds in small colonies on rocky islands and cliffs of the northern Pacific. The deposits extend from Kamchatka to North America and thence along the coast from Alaska to California. In winter, the Taubenteisten of Alaska to the ice-free ocean areas in the south. California birds migrate, however, to the north in the area of British Columbia.

Food

Taubenteisten look for food near the coast in shallow water zones with a growth of underwater plants. In their search for food they hold approximately within a radius of ten kilometers from their breeding colony.

When foraging Taubenteisten start their dives from the water surface. They remain in the upper water layers and catch fish, crustaceans and other marine animals. The maximum, previously determined depth is 30 meters, but they prefer waters with a depth of 10 to 20 meters.

Reproduction

As the other species of the genus, and in contrast to most other Alkenvögeln sets the Taubenteiste two eggs. This is probably related to the fact that foraging takes place in the vicinity of the breeding colony, which allows them due to short paths, procure sufficient food for two nestlings. The breeding colonies are found on islands and headlands with a sufficient supply of rock crevices and rocky beach and to nearby areas of shallow water with a rocky ground. Where predatory mammals such as rats, foxes, mink or raccoon occur, the breeding colonies found only in inaccessible cliffs. The Taubenteiste is a colony breeders, but the colonies are generally very small and usually include a dozen to a hundred breeding pairs. Larger colonies are rare. The species is very loyal and hatchery uses its nesting hole several times. This is associated with a high partner fidelity.

As Niststandort rock slots are used, which have a depth in the rule that the breeding bird is no longer visible from the outside. The eggs are laid in a shallow depression lined with small pebbles on the ground. Taubenteisten dig but also sometimes nests or use caves under tree roots or the abandoned burrows of other sea birds or rabbits. Among the more unusual nest sites of Taubenteiste include small cavities under ship system, bridges and shipwrecks. Nests have also been found in disused buildings. The Niststandort is not removed more than 30 meters from the water line usually.

The beginning of the breeding season varies depending on the particular environmental conditions by up to a month. Usually begin breeding birds in California, Oregon and Washington in the first half of May with the breeding business. In British Columbia, however, is the onset of lay in the second half of May until the beginning of July. Taubenteisten has already seen 40 days before the onset of lay increasingly in the colony. Both parents birds breed and have a brood patch, which is large enough to cover both eggs. The two nestlings hatch usually at a distance of one to two days, their hatching weight is on average 43.7 grams. However, they are brooded by a parent bird in each continuous at least up to their third, usually until their seventh day of life. The nestling food is from the outset fish that is eaten cut in pieces by the nestlings. The adult birds each bring a single fish to the nest, they usually wear a cross in its beak. The parent birds wear during the day and per hour Nest zoom statistically from 0.7 to 1.9 fish.

The nestling period is an average of 38 days and varies 30-53 days. The young birds weigh between 300 and 400 grams when they leave their nest. They reach either running or fluttering the water. To date there is no evidence that the parents birds their young after leaving the nest continue to serve. On average, a young bird per breeding pair and year will fledge.

Predators and age

The main predators include rats eat the eggs and nestlings. The North American river otter (Lutra canadensis) monitored regularly to individual breeding colonies. Among the predators also include raccoons and the Great Whale. Western gulls, Bering gulls, great horned owls, bald eagles, peregrine falcons and Sundkrähen are more predators.

100 adult Taubenteisten die per year 20 The average expected life span of six years. The oldest found to date ring bird had an age of 14 years.

Stock

The stock of Taubenteisten considered stable, but there are few data on population trends of this kind, the total stock breeds in hundreds of small colonies in a very large area of ​​distribution, so that inventories are difficult and completely lacking in some areas. On the Russian coast probably breed tens of thousands of Taubenteisten. The stock of the breed in Alaska Taubenteisten was estimated by the United States Fish and Wildlife Service in 1993 to 200,000. British Columbia has 10,200 6,000 Washington, Oregon and California 3500 to 15,470 Taubenteisten. The largest breeding colony is located on one of California's Farallon Islands. Among the sources of risk include, among others, the oil pollution of the sea, the Taubenteisten were affected, for example, the accident to the super tanker " Exxon Valdez " in 1989. Since Taubenteisten, however, are spread over numerous small colonies, the impact of such disasters on the total stock is not very high. Negative impact of the introduction of predatory mammals. Example, it was exposed to the Aleutian Islands of the Arctic fox fur breeding for the purposes of which endangers the ground-nesting Taubenteisten. In British Columbia, the area expansion of raccoons for this kind a risk;

Subspecies

We distinguish the following sub- types of Taubenteiste:

• Ceppphus columba eureka Storer, 1950 - West Coast of North America from Oregon to California
• C. c. adianta Storer, 1950 - North American west coast from Washington to Alaska and the Aleutian Islands
• C. c. kaiurka Portenko, 1937 - Aleutian Islands on the Andreanof Islands, Delarof Islands, advice Iceland and Near Islands to the Commander Islands
• C. c. columba Pallas, 1811 - Siberian coast of the Bering Strait to the southern tip of the Kamchatka Peninsula and the coast of Alaska
• C. c. snowi Stejneger, 1897 - occurs on the Kuril Islands

The body size of the species increases from California to the Aleutian Islands off continuously.

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