Steppe gull

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Steppe gull
Steppe gull (Larus cachinnans)

Steppe gull ( Larus cachinnans )

Systematics
Class : Birds (aves)
Order : Plover-like (Charadriiformes)
Family : Laridae
Subfamily : Seagulls (larinae)
Genre : Larus
Type : Steppe gull
Scientific name
Larus cachinnans
Pallas , 1811
Steppe gull in youth dress . In contrast to the Mediterranean seagull, the white hems of the shoulder and coat plumage are only narrow, the feather centers are quite light. The white hems of the dark umbrella feathers usually only reach to the middle and not to the large arm covers.

The steppe gull ( Larus cachinnans ) is a relatively large species of bird among the gulls (Larinae). It is native to southern Eastern Europe and western Central Asia , where it breeds from the Black Sea to eastern Kazakhstan . However, there are also scattered breeding occurrences as far as Central Europe ; the largest are in Poland. In Germany the species breeds sporadically in the east. After the breeding season, especially many young birds migrate to the northwest and are then found scattered as far as Western Europe . The main wintering areas are in the Middle East .

The systematic position of the steppe gull was controversial for a long time, it was regarded as a subspecies of the herring gull , then also as a subspecies of a new taxon "white-headed gull". In 2001, the paraphyly of this taxon was determined by molecular genetic studies and the two forms, steppe gull and Mediterranean gull, which are combined there, were granted species status.

description

The steppe gull is 56–68 cm long and has a wingspan of 137–145 cm, about the same size as a herring gull. In terms of physique, however, it is similar to the somewhat smaller lesser black-backed gull to which it is more closely related. It often appears slim with a relatively small head, a slim abdomen sloping straight back and high legs. The head is elongated, the forehead flat and the back of the head angular. The beak is not very strong with only a weak angle of the gonys and a long nostril. The eye looks small and sits relatively far in front and at the top of the head. Sex dimorphism is not pronounced. Young steppe gulls switch to adult dress after the fourth winter .

Adult birds

Adult steppe gulls in breeding dress have a yellow to greenish yellow bill with an orange or red gony spot . The iris is usually brown to yellow-brown, but sometimes also yellow-gray with dark speckles, so that the eye appears dark at least from a distance. In some populations, the proportion of birds with light eyes predominates. The eye is enclosed by an orange or red orbital ring. The head, neck, chest, front back, underside, rump, and control feathers are pure white. The top is light gray. It lacks the bluish tone that is often found in herring gulls. On the upper side of the wing there is a wide, white rear edge, which ends in the area of ​​the black wing tip as a row of white hand-wing tips. The outermost hand swing shows a very broad, white tip, the penultimate a white subterminal field . The proportion of black on the hand wing is smaller than that of the Mediterranean gull and greater than that of the herring gull. The black coloring usually extends up to the fifth wrist arm, on which it is only present as a subterminal marking. It is noticeable that the gray of the upper wing protrudes into the black of the outer hand wing in the form of very extensive "tongues", which is due to the largely gray inner veins of the outer hand wings. The basic color of the legs and feet is gray and can have either a yellowish or a flesh-colored tint.

In the plain dress, the head shows a rough, dark dash around the eye in the area of ​​the neck and a slightly finer one on the crown. The beak is greenish yellow. Often dark markings are mixed into the matt-colored gonys' spot, which sometimes extend to the upper beak and form a subterminal band.

Subadult birds

Steppe gulls in their juvenile plumage are similar to juvenile Mediterranean seagulls (especially those of the eastern populations), so that it is often particularly difficult to distinguish them in the field. The beak is black, the eye dark; the legs and feet are flesh-colored. Head, chest and underside are dashed brown on a whitish background. The dotted lines condense around the eye, on the neck, sides of the chest and flanks. The top and the arm covers appear scaled due to dark or dark banded feather centers and light hems. The fringes, however, are usually narrow and the dark centers relatively light, so that the drawing, in contrast to that of Mediterranean seagulls, appears less rich in contrast or washed out. From the brownish back stand out the mostly very monochrome dark umbrella feathers , which show a wide, white border in the distal third, which rarely reaches the large arm covers in the seated bird. As with the black-backed gull, the arm cover area is marked by two light transverse bands. The rest of the wing plumage is blackish brown. The inner wings of the hand are lightened and, in flight, form a bright field, which, due to the dark outer flags, appears streaky like blinds. The rear edge of the wing is white due to the light-colored wing tips except for the middle hand wing. On the lower wing are relatively large, uniformly white areas. The rump shows a light grayish-brown wedge that merges into the white, partly brownish-banded upper tail-covers. The white tail has a broad, dark band that ends in fine banding towards the base.

The first plain dress looks “four-colored”: the black beak and the dark umbrella feathers and hand wings contrast the predominantly whitish head and the underside. The back plumage is predominantly light gray with varying dark markings and stands out from the gray-brown arm covers of the youth dress, in which some new, grayer feathers can already be mixed. The base of the beak may already be slightly lightened. In the white areas of the head and the underside, there is a dirty gray "neck ruff", a slight dash around the eye from which the white eyelids stand out, a slight dash on the flanks and a banding of the outer underbelly.

In the second winter, the beak is usually flesh-colored with a dark front bill and a light tip. Some birds still look very late as in the first plain dress, but the contrast between the coat and shoulder plumage and the arm covers is less. In other birds, the upper side is almost predominantly light gray, only small and large arm covers are still banded in brown. There are now very wide, somewhat patterned, white edges on the dark feathers. The upper tail-coverts and the basal part of the tail are now pure white, the rump is light gray.

The third plain dress is already very similar to the adult winter dress, but the beak has not yet been colored and wears a dark subterminal bandage. In the area of ​​the hand covers there are still many blackish feathers and on the tail there are still remnants of a dark band. In the fourth winter, extensive dark markings in the area of ​​the front bill indicate that the bird is not an adult.

distribution

Distribution of the steppe gull:
  • Breeding areas
  • Year-round occurrence
  • Wintering areas

    • The main brood distribution of the steppe gull extends from the Bosporus eastwards to Lake Saissan in eastern Kazakhstan . The southern boundary of the distribution runs through the northern part of the Black Sea, the Azov Sea and the inland lakes of the northern Caucasus foothills to the Caspian Sea , where the species southward breeds up to the height of the southern center, on the Aral and Balkhash to about the Issyk Kul . In the north the steppe gull settles along the lower reaches of the Dniester , Dnieper and Volga . In Russia it is still scattered northwards to Moscow . It has also been breeding in the region around Bucharest since 1979 and has since spread across the Central European river systems in scattered occurrences to Hungary, Belarus, the Czech Republic, southern Germany and Poland.

    habitat

    The breeding habitats of the steppe gull are on islands, in lagoons and estuaries on the Liman coast of the Black Sea and the Caspian Sea as well as on inland lakes in steppes and semi-deserts, and more rarely on rivers and their oxbow lakes. The nesting sites are found in inaccessible places such as islets, sand dunes or open spaces within dense reed beds. These are mostly places with little vegetation, but the shade of bushes is sometimes used. The species occasionally nests on roofs on the Bulgarian Black Sea coast and in Bucharest.

    Outside of the breeding season, the steppe gull occurs on all coastal forms and inland waters.

    Duration

    The total European population of the steppe gull amounts to 30,000 to 50,000 breeding pairs. The largest populations are found in southern Russia, southern Ukraine, Romania and Azerbaijan. The Central European distribution center is Poland, where 230 to 240 breeding pairs occurred at the beginning of the 21st century.

    Steppe gulls east of the Caspian Sea hardly differ from the subspecies L. f. barabensis the     black-backed gull

    Systematics

    The steppe gull was previously considered a subspecies of the very similar herring gull . In the 1980s, the yellow-legged populations in the adult dress were subdivided into a taxon called "White-headed gull" ( Larus cachinnans ) - a name that is quite appropriate, as in the first few years the birds appear very "white-headed" in contrast to the herring gull. At the turn of the millennium, however, it was established on the basis of genetic studies that the “white-headed gull” is a paraphyletic taxon. It was therefore split into the Mediterranean gull ( Larus michahellis ) and the steppe gull ( Larus cachinnans ). The assumed subspecies L. c. omissus , however, turned out to be the yellow-legged variety of the herring gull. It was also found that the steppe gull is more closely related to the black- backed gull than to the herring gull.

    For some time, the affiliation of two forms from western and southern Siberia - barabensis and mongolicus - was also controversial . Because of numerous external similarities, they were temporarily placed as the steppe gull. According to molecular genetic studies, however, barabensis is close to the black-backed gull (and especially its subspecies L. f. Heuglini ) and is now mostly regarded as a subspecies thereof , whereas mongolicus is classified as a subspecies of the Eastern Siberian gull ( Larus vegae ). The steppe gull is therefore monotypical . Birds of the steppe gull population east of the Caspian Sea are very similar to Larus fuscus barabensis and a reliable identification is often not possible. The exact differentiation between the forms as well as their exact distribution and overlap require further investigation.

    literature

    Web links

    Commons : Steppe Gull  - Collection of images, videos and audio files

    Individual evidence

    1. ↑ a b c d e f g Olsen / Larsson (2003), p. 308f, see literature
    2. ↑ a b Glutz von Blotzheim, p. 610
    3. ↑ a b Olsen / Larsson (2003), p. 325, see literature
    4. ↑ Glutz von Blotzheim, p. 611, see literature
    5. ↑ a b Del Hoyo et al. (1996), see literature
    6. ↑ Bauer et al., P. 612
    7. ↑ a b J. M. Collinson, DT Parkin, AG Knox, G. Sangster, L. Svensson: Species boundaries in the Herring and Lesser Black-backed Gull complex . British Birds 101 (7), 2008
    8. ↑ Olsen / Larsson (2003), p. 322, see literature