Uria

Guillemot between two thick-billed murres

The guillemots (Uria ) are a two ways comprehensive bird genus which belongs to the Alkenvögeln ( Alcidae ).

The guillemots are marine birds that are widespread in the northern hemisphere. Only during breeding time is spent on the coasts.

Appearance

Both types, the common guillemot (Uria aalge ) and thick-billed murre the (Uria lomvia ), 38-46 cm tall and about 1 kg. After the mid-19th century extinct Great Auk ( Pinguinus impennis ), they are the largest Auks.

Guillemots are colored black on the upper side and lower side white. In winter plumage, the white color also extends to the black in breeding plumage throat. The beak is uniformly black in color. In the guillemot there is a color variant that Ringellumme, with a white eye ring, from which a curved white stripe one piece neck down pulls.

Dissemination

The breeding range of the common guillemot extends beyond the shores of the North Atlantic and North Pacific and over the adjacent Arctic Ocean coasts. The range extends south in the Atlantic area to the British Islands and Portugal, in the Pacific to Korea, Northern Japan and California. The guillemot also breeds on Helgoland, where she lives on the " Lummenfelsen " so-called.

Thick-billed murres breed further north in the Arctic waters; their southernmost occurrences are in Iceland, Newfoundland, Sakhalin, the Kuriles and the Aleutian Islands in Alaska in.

Reproduction

Guillemots nest in colonies on rocky ledges and cliffs in inaccessible cliffs. The female lays only one egg directly on the rock surface. During the incubation, the eggs lying on the webbed the adult birds. The pear- shaped, individually subscribed eggs are 8.1 x 5 cm in size. Due to its shape the Lummenei rolls poorly, which is advantageous to the often narrow ledges.

Even in down dress dare flightless, three week old chicks guillemot the jump in the up to 40 meters deep below them the sea. Here they are (usually the father) further fed by their parents until they are able to fly.

This unusual behavior has evolved since the adult animals are quite heavy and have relatively small wings. So they can not carry a lot of food for the young birds in flight. Once the young birds are larger and require more food than the parents can bring along the fly, it comes to the so-called Lummensprung. So this behavior adjustment compensates for the physical disadvantage which results from the relatively poor flight ability of adults for the boys - rearing.

The Lummensprung can be observed for example in the summer on Helgoland.

Species

• Guillemots (Uria ) Guillemot (U. aalge )
• Thick-billed murre (U. lomvia )

Phylogeny

Morphological as well as genetic studies revealed a close relationship of guillemots (Uria ) with the genus Alca, whose only living representative of the Razorbill is today. While there are numerous fossil record of the genus Alca in the area of the Atlantic, only two fossil evidence for guillemots, Uria affinis namely from the Pleistocene of Maine and Uriah ausonii from the Pliocene of Italy are known. ( The latter type is assigned by some authors, however, of the genus Alca. ) Furthermore, there are only two other fossil Uriah discoveries, namely: Uriah and Uriah brodkorbi paleohesperis from the Miocene or Miocene / Pleistocene boundary of California. After Warheit the geographical distribution of these findings lead to the hypothesis that the genus Uria developed in the Pacific and spread into the Atlantic between the early Pliocene and Pleistocene of the Arctic seas. Olsen and Rasmussen lead the absence of Uriah the Atlantic to the late Pleistocene to a competitive situation with Alca back. Uriah representatives were not allowed into the Atlantic foothold emerged as appropriate niches.