Belcher's Gull

Adult Simeonsmöwe (Larus belcheri ) in breeding plumage

The Simeonsmöwe or Schwanzbandmöwe (Larus belcheri ) is a species of bird in the family of gulls ( Laridae ). They colonized the west coast of South America in the area of the Humboldt Current.

The very similar Olrogmöwe (Larus atlanticus ) from the east coast of South America has long been regarded as a subspecies of Simeonsmöwe. Both belong in the genus Larus to a fairly original group of four species that carry a dark tail band in all the dresses and show in the adult dress relatively simple beak drawings and almost completely black primaries.

The specific epithet honors the British navigator Sir Edward Belcher, who collected the first specimen of its kind.

Description

The Simeonsmöwe is 48-52 cm body length and a wingspan of 120 cm slightly smaller than a herring gull. But reminds her head shape and the powerful beak of larger gulls. From the very similar Olrogmöwe the species differs by shorter wings, a shorter beak with less pronounced Gonyswinkel, a mushy transition from the jacket to the neck and a brownish top.

In breeding plumage the head, neck and underparts are white. The yellow beak points ahead of the red tip on a broad black subterminal ring. The dark iris is framed by a red orbital ring. The plumage of the top is brown and black runs along the neck washed out in the White of the neck. The inner part shows a white wing trailing edge. The hand wing is almost completely black and shows except at the inner primaries no white tips and no notable pattern as with other Larus species. The white tail carries a wide black Subterminalbinde. Feet and legs are yellow.

In winter dress show adult gulls Simeon a dark head, washed on the upper neck merges its color in the white of the underside. Of these, small white half rings stand out to the eye.

In juvenile plumage the head is sooty brown, yellow beak with black tip. The underside is gray-brown with lighter underbelly. The dark plumage coat and shoulders acts scaled by light rims. The deck feathers of the wings and the springs show screen on a dark background only a diffuse pattern. The inner wing trailing edge is whitish. The tail is black, the legs are dark brown to dark flesh color.

In the first winter coat and shoulders are bright, spring centers are less extensive. The dark head contrasts strongly with yellow beak and the bright bottom.

In the second winter coat and shoulders are already brown black as in adult birds that are still brown upper wing-coverts stand out from it. The head cap is similar to the adult birds, however, the transition to the neck is way more diffuse. The beak is almost fully colored, the red tip but not as intensely red as in older birds.

Voice

The calls of this type are described as short, clear jap or Jiau. The " shout " (long call) ( Sample ) is an up -enhancing Rufreihe from clear sounds.

Distribution and population

The monotypic Simeonsmöwe colonized the South American west coast in the area of the Humboldt Current, where the breed spread about by the Peruvian region of La Libertad to the northern Chilean region of Tarapacá enough. Outside the breeding season is the way to find north to northern Ecuador south to central Chile.

The world population is estimated at less than 100,000 breeding pairs and it is only a small number of larger breeding places known. In Peru, the species is quite common. Much of the breeding population is concentrated in the island of San Gallán in central Peru. The species is classified by the IUCN as not at risk ( " least concern ").

Hiking

The Simeonsmöwe is probably largely sedentary, but find it sometimes in the area of the Humboldt Current Dismigrationsbewegungen in the north and south instead. As Irrgast the species was found in Panama and Florida.

Way of life

The Simeonsmöwe feeds on fish, crustaceans and carrion. During the breeding season are bird eggs and nestlings of other species of importance. The food is wanted on beaches, in the intertidal zone and in seabird colonies. The type rarely follows ships out to sea.

The breeding colonies are located on rocky coastlines and coastal guano islands and be occupied from December. They usually have a size of less than 100 pairs. There are few places exceeds the number of breeding pairs in 1000. The nesting sites are located in rock crevices or in the sand. Here, the eggs are often stored without a nest is built. The nest usually consists of three dark olive-brown eggs.