Black-headed gull

from Wikipedia, the free encyclopedia
Black-headed gull
Black-headed gull on the southern edge of its range in Ars-en-Ré

Black-headed gull on the southern edge of its range
in Ars-en-Ré

Systematics
Class : Birds (aves)
Order : Plover-like (Charadriiformes)
Family : Laridae
Subfamily : Seagulls (larinae)
Genre : Larus
Type : Black-headed gull
Scientific name
Larus marinus
Linnaeus , 1758
Black-headed gull in flight. Compared to other seagull species, the wings are relatively short and wide with short hand wings.
Mantled gull in the first winter. Due to the combination of a whitish head and contrasting and coarsely patterned coat plumage, the species is easy to determine. In addition, the high, dark beak is noticeable, which only brightens at the base in the second winter.
Mantled gull after the third winter - with an already dark back and still brownish wing plumage

The black-headed gull ( Larus marinus ) is the largest bird species among the gulls (Larinae). It is native to the coasts of north and north-west Europe, in Greenland and in north-east North America. However, the species is absent as a breeding bird on the Wadden Sea coast of the North Sea. In Europe, Norway, Great Britain, Iceland and Sweden hold the largest stocks. While the High Nordic populations migrate south or westward in winter, most of the other birds are resident .

The black-headed gull is largely tied to the seashore, where it nests in inaccessible places such as islands or rocky cliffs. Not infrequently it breeds in colonies of other gulls and then occupies the highest, most exposed places. It mainly feeds on animal food and waste. They often prey on other birds or hunt their prey from them, but in many places they also feed on fish and other marine animals.

The black-tailed gull populations have increased significantly over the course of the 20th century. Especially in North America, where the species has also expanded its range, the population development was almost rapid.

description

With a body length of 61–78 cm and a weight of usually 1.5–2 kg, the black-headed gull is the largest species of gull . The wings are relatively short and wide with a wingspan of 145–165 cm; in the seated bird they barely protrude beyond the tail. In flight the species looks compact and flies with strong, slow wing beats. In the flight it is reminiscent of a sea ​​eagle - not least because of the relatively short tail and the long protruding head . In the sitting bird, the relatively large head and powerful beak are also noticeable. The legs are also strong with a relatively long visible part of the tibiotarsus . With this species, the difference between the sexes is often particularly evident. Males show a slightly "brutal" facial expression due to the strong cheek area and the eye that is positioned far back and at the top of the head. Females often only reach the size of herring gulls, but appear stronger overall with a strong beak, a flatter crown and a smaller eye. The sexes cannot be distinguished on the plumage. Young black-headed gulls are fully colored in their fourth year of life. The species is monotypical .

Adult birds

Adult birds in breeding plumage show a light yellow beak with a red gony spot ; the otherwise gray-pink legs can have a yellowish tinge. The iris is pale yellow to amber, the eye is surrounded by a red or orange orbital ring. The head, like the neck, nape, underside, rump and tail, is pure white. The blackish slate gray of the upper side hardly stands out from the black wing tip, which is not very extended. The tip of the outermost hand-wing is broadly white; sometimes there is a dark spot on the outside flag in the white field. The penultimate hand swing shows a subterminal white field. The tips of the other hand wings are white, those of the arm wings form a wide white rear edge of the wing. A dark wing band can be seen on the lower wing. In the sitting bird, in addition to the large, white tips of the hand wings, the wide white edges of the umbrella feathers are noticeable.

In the simple dress, the head around the eyes, on the ear covers and in the neck is dotted with fine dark brown lines. The white "eyelids" stand out around the eye. The dashed lines on the head are very fine and sometimes hardly noticeable from a distance. The beak is pale yellow, the gony's spot orange and sometimes interspersed with dark markings.

  • Males in particular show a somewhat “brutal” facial expression due to their strong cheeks and high-set eyes

  • In the breeding dress, the legs can be tinged with yellow

  • Young black-headed gull in the first summer. The base of the beak has already lightened considerably.

  • A very bright specimen in the first summer.

Subadult birds

Young birds appear whitish gray-brown with a roughly patterned, dark top. In contrast to the herring gull, they appear much more contrasting black and white, similar to Mediterranean seagulls , but more strongly patterned. The bill and iris are dark, the legs flesh-colored. The head, chest, anterior back, rump and underside are relatively sparse, dark gray-brown dashed on a whitish background, with the dashed lines condensing on the vertex, around the eye, in the neck, on the sides of the chest and flanks. It is also coarser on the flanks and front back. The coat is dark and has an almost plaid-like pattern due to its wide, white hems. The elytra are roughly banded dark-whitish and lightly lined, the umbrella feathers dark with a wide, white border. The wings are blackish, the inner hand wings are lightened and form a bright field in the flying bird. The whitish tips of the arm-wings and the inner hand-wings form a white trailing edge. The upper tail-coverts are white with sparse banding. The control feathers show a dark, relatively narrow subterminal band on a white background , which tapers towards the rump. The outside of the tail is usually white.

The first plain dress is similar to the youth dress, but the head and chest are clearly whiter with fine, dark dashed lines that are concentrated around the eyes and neck. The beak lightens slightly flesh-colored at the base. Mantle and shoulder feathers are much lighter and have a subterminal, arrow-shaped, dark mark on a beige background. They can still be mixed with individual feathers of the youth dress. Some specimens look very light in their bleached plumage, especially in summer. The dark tail band often breaks up into several narrow bands.

In the second winter, the base of the beak is already significantly lightened, but the plumage is still very similar to the first plain dress. The large arm covers are freshly moulted and more finely banded on a beige background than in the first winter. In flight they contrast as a lighter field with the dark arm wing. The wings of the hand have fine white lace hems; the white tips of the wings are much more extensive. A light mirror can already be indicated on the outermost hand wings. The dark tail band appears diffuse. Only a few specimens have individual back feathers from the adult dress.

In the second summer, many dark gray feathers mix in the back plumage and individual arm covers are also dark gray. From the third winter onwards, almost all of the coat and shoulder plumage and the middle arm covers are dark gray. The largest part of the hand wing already shows the characteristics of the adult dress. In addition, the small brown arm covers, hand covers and arm swings contrast conspicuously. The dark tail band is still indicated in stripes. Birds in the fourth winter differ only slightly from adults. The top can still look a bit brownish and the hand covers can still be very dark. In the area of ​​the front bill, the dark markings are often quite pronounced.

  • First winter

  • Second winter

  • Third winter

  • Fourth winter

Hybrids

The black-headed gull occasionally hybridizes with other large gulls. The hybrids then often have intermediate characteristics and are difficult to identify . In Greenland, for example, hybrids between the mantled gull and the ice gull occur regularly. These are a bit darker on the top than ice gulls and, in their hand-wing pattern, are reminiscent of the black-tailed gulls. Hybrids between the herring gull and the American herring gull are also known. In Denmark and Finland, some birds have also been identified as presumable hybrids between the black-backed and black-backed gull .

In a colony of great gulls on the roof of the Posthof in Frankfurt am Main, a mixed pair of mantled and Mediterranean gulls has been breeding since 2009 . One of the resulting hybrids successfully raised two young with a Mediterranean seagull in 2015.

voice

As with all seagulls, the reputation repertoire of the black-headed gull is very diverse. Compared to those of the herring gull, the calls are deeper and louder, sometimes they sound much hoarser or chatter like a duck. Call series are usually presented more slowly. The Hauptruf is a deep, often raucous and sometimes loud peals of kau or krau . The shouting ( "long call" ) begins with two relatively long, deep sounds, increases to a series of calls made up of high sounds and then mostly flattens out again towards lower sounds. In contrast to the herring gull, however, the high call elements “exceed” one another which cannot be penetrated by i- sounds. The “cat call” ( “mew call” ) that can be heard between partners as an intimate contact call is a deep, guttural maau ; a duck-like cackling series of calls ("staccato call") can be heard as an alarm call.

distribution

The distribution area of ​​the black-headed gull is in the area of ​​the North Atlantic and the Baltic Sea on coasts and islands in the temperate, boreal and subpolar zone.

In the western Palearctic it populates Iceland , the Faroe Islands , Svalbard , the Bear Island , Waigatsch and the Kanin Peninsula , Kolgujew and the south of Novaya Zemlya , Fennoscandia from the Murman coast westwards and the coasts of the Baltic Sea to the Kattegat . In the North Sea it occurs on the Skagerrak and the coast of northwest Jutland , in the area of ​​the Wadden Sea and on the English west coast from Plymouth to the Firth of Forth it is largely absent as a breeding bird. She populates the rest of the coasts of the British Isles as well as the Channel Islands . In France it occurs in Normandy and Brittany southwards to the Loire-Atlantique department .

In Greenland, the black-backed gull breeds on the east coast only near Tasiilaq and on the west coast from the Nuussuaq peninsula south to Cape Farvel .

In the Nearctic, the species breeds on the north east coast of North America. The northernmost occurrence is here at the mouth of the Rivière aux Feuilles on Ungava Bay . From Cape Chidley in northern Labrador it then extends south on the coast over Newfoundland to the coasts of the St. Lawrence Gulf and the St. Lawrence River up to Montreal . The species also occurs on the coasts of Anticosti , the Magdalene Islands , Prince Edward Island , New Brunswick and Nova Scotia . In Ontario it breeds scattered on the north bank of Lake Ontario and on the east bank of Lake Huron . In the USA, the occurrence on the coast ranges from Maine to New Jersey . The black-backed gull also breeds on the Delmarva Peninsula in Maryland and Virginia , on the coast in the far north of North Carolina and scattered on Chesapeake Bay in Maryland. There are individual breeding records from Vermont and Delaware .

hikes

In the Great Lakes area, the number of wintering black-headed gulls is increasing.

The black-headed gull is a line or migratory bird . Up to the pack ice border , some of them persist in the breeding grounds in winter; the high arctic populations migrate regularly. In the southwest of the range, but also on Iceland and the Faroe Islands, there are many resident birds , other birds usually only migrate short distances and gather in particularly food-rich areas. The main European wintering areas are in the southwest of the Baltic Sea, on the North Sea, in the coastal waters of the British Isles, in the English Channel and on the Bay of Biscay . In the area of ​​the Dutch Wadden Sea coast, up to 100,000 birds sometimes overwinter, while the winter populations in north-western Europe include up to 480,000 birds. Smaller numbers also reach further south to North Africa and the Mediterranean area.

Northern Russian and Northern Norwegian birds migrate in large numbers along the Norwegian coast to winter on the North Sea, in the area of ​​the British Isles, or in smaller numbers further south. Southern and western Norwegian birds predominantly migrate to north-west England. The Baltic populations overwinter between the Baltic Sea and the Kattegat with the largest accumulations on the Belten and in the Kattegat.

In North America, the main winter quarters are on the Atlantic coast between Newfoundland and New Jersey, where there are sometimes collections of up to 3000 birds. In recent decades, however, the species has increasingly appeared further south and in the area of ​​the Great Lakes as a winter guest.

The first noticeable migratory movements are from July, mostly younger birds, non-breeders and birds without breeding success. The colonies are cleared from August, the main migration takes place with locally different maxima between September and November. Most train movements are largely completed in November, but winter escapes sometimes take place later. The largest stocks are found in the winter quarters between November and February. The home move takes place between the end of February / beginning of March and April. Even in the far north, the first birds arrive in the breeding areas from March. After April the train is locked almost everywhere.

Non-breeders spend the summer in their winter quarters or somewhere between the wintering place and the place of birth, but they can also be found far away from these routes.

habitat

The black-headed gull is tied to the seashore even more than other gulls and rarely appears inland, at most in winter in the coastal hinterland. In North America and Scandinavia, however, it also occurs on large lakes (e.g. Lake Ontario or Inari Lake ).

Breeding sites must be safe from soil enemies and are therefore usually located on islets, rocks or skerries. Sometimes the species nests in colonies of other seagull species and then chooses the highest places with the least vegetation. The breeding grounds are rarely found on broader, grassy strips in steep cliffs. In Iceland in particular, extensive flushing fringes, moraines , gravel areas and sandbanks are also accepted on the coast and at river mouths. In Great Britain the species also breeds in moorland and on islands in larger lakes and rivers; the number of breeding pairs in the interior is less than 1% of the total population. In North America, the species also breeds in salt marshes and dunes, and occasionally on roofs in cities.

Outside the breeding season, the black-headed gull can be found on rocky and sandy coasts, at large estuaries and in the open sea. Landfills and fishing ports are very attractive. The sleeping places are almost always on the coast; often large open areas such as fields, parking lots and sometimes runways are chosen. The species only penetrates inland so far that it can return to the coast in the evening.

nutrition

A black-headed gull captures a young eider in spite of fierce resistance from two female eiders.

Like other gulls, the black-backed gull feeds omnivorously and opportunistically, but the focus is clearly on animal food and waste. These include fish, mollusks , crustaceans , cephalopods , annelids , insects , starfish and other echinoderms , birds up to the size of a shag , fledglings and eggs, mammals up to the size of rabbits or young lambs, carrion, rubbish and fishing waste. In addition, there is plant food such as berries, seeds and arable crops.

Eating behavior changes seasonally. While the species predominantly fish, forage or predatory feeds in the summer half of the year and fish provide a large part of the nestling food during the breeding season, it lives mainly on waste in winter.

However, kleptoparasitism plays a role year-round. The parasitized species include waterfowl such as loons , sea ​​ducks and sawsmen , but also other gulls, ospreys or sea eagles and even porbeagle sharks .

In sea bird colonies, nests are plundered and young birds are captured. Migratory songbirds, as well as sea birds such as storm or terns and even ducks are attacked in flight or on the water and - usually by drowning - killed.

The black-headed gull often catches fish by thrusting, shaking or after a short landing on the surface of the water - mostly near fishing trawlers or on rocks and sandbanks lying under water, where many creatures gather. Often, however, fish or invertebrates that have stayed behind or washed ashore are also captured in tidal pools or in tides at low tide. It is not uncommon for the seagull to transport fish that are heavier than itself.

Reproduction

Brooding black-headed gull
Gelege, Museum Wiesbaden collection

Black-headed gulls become sexually mature at the earliest four to five years. If a partner is too young, the couples concerned can build a nest without laying eggs. There is an annual brood; the couples come together for a monogamous seasonal marriage.

The black-headed gull usually nests individually or in smaller colonies, and more rarely large gatherings of a few hundred to 5000 birds occur. Often the species joins colonies of other seagull species, in which it often breeds in loose groups of a few pairs. Sometimes the breeding site is visited as early as winter, but is usually not permanently occupied until March or April.

The nesting site can be very variable, but a noticeable preference for elevated locations, which can often be quite exposed. These can be on pinnacles or small hills in the middle of islands, on ledges or ledges in cliffs. Broods were also rarely found on roofs. Usually the nesting place is only sparsely overgrown; a sward is preferred to bare rock and sometimes the nest is hidden in the vegetation (for example in dwarf shrubs). Sometimes it can also lean against a rock or tuft of grass or be erected in a crevice.

When building the nest, a hollow is first dug out and then lined with parts of plants such as grass, heather or seaweed and with feathers. The nesting material is often stolen from other species of gulls, and sometimes entire nests are taken over. The nest size is between 30 and 60 cm, the trough is about 25–30 cm wide and 5–10 cm deep.

The main laying time is in April and May, but shifts to the north and, as in Greenland, can also be the beginning of June. The black-headed gull always breeds earlier than the herring gull - in North America, the start of the breeding season for the two species is about two weeks apart.

The clutch usually consists of three, more rarely two eggs; larger clutches come from several birds. The eggs are laid over five to six days. At around 77 × 53 mm, the eggs are much larger and lighter than those of the herring gull and herring gull . On a light gray, beige, brownish or light olive ground, they are irregular and coarsely speckled, smooth and relatively lackluster. Incubation begins with the first or second egg and lasts 26 to 28 days. Both partners brood.

The young leave the nest within the first 24 hours. They are still huddled up to the age of 7-10 days . Both partners also take part in this, as well as in feeding. The young birds learn to fly at the age of 45–50 days. After 50–55 days they leave the vicinity of the nesting site, but occasionally return there up to 10–11 weeks of age.

  • Clutches with three eggs are the norm

  • Hatching chick

  • Two down boys

  • An older cub is being fed

Mortality and Age

Black-headed gulls can live to be over 20 years old: A black-topped gull that was ringed in Finland reached the age of 27 years and a month, while an animal ringed on Heligoland was at least 20 years and a month old.

Inventory development

The world population of the black-headed gull is estimated at 540,000–750,000 adult birds. The European population (including Greenland) amounted to around 110,000–180,000 breeding pairs around the year 2000, with Norway with 50,000, Great Britain with 17,500, Iceland with 15–20,000 and Sweden with 10–15,000 breeding pairs holding the largest populations. According to surveys between 1975 and 1996, around 65,000 pairs breed in the Nearctic, including over 25,000 in Canada and over 38,000 in the USA.

As with other seagulls, the stock of the black-headed gull increased sharply in the course of the 20th century, which was initially due to the decline in persecution and later to improved feeding conditions due to the abundance of rubbish tips and fishing facilities. This was accompanied by large area expansions. In 1907 Estonia, 1921 Bear Island, 1925 France (first on Sept Îles ), 1930 Svalbard and Denmark (initially only Læsø ) were settled.

The spread in North America was particularly spectacular, where the species was still missing as a breeding bird in the New England states in 1914. In 1928 she first brooded in Maine, in 1931 there were already 25–35 breeding pairs in eight different locations. In 1965 there were 9,847 breeding pairs there; there were a total of 15,000 on the east coast of the USA. Between 1926 and 1965 the population grew by 17% per year. The trend remained increasing. In 1977 17,405 breeding pairs were counted along the coast from Maine to Virginia, which had increased to 30,780 in 1984 and 38,642 in 1994 and 1995.

Up until the 1970s, the number of populations in Europe increased, sometimes slowly, sometimes almost exponentially. After 1970, the numbers mostly stabilized at a high level or continued to rise locally. The species first brooded in Germany in 1984 and in the Netherlands in 1993. The German population currently comprises 46–52 breeding pairs. In Great Britain, a further increase in population between 1970 and 1980 was largely prevented by decimation measures. While 22,450 breeding pairs were still recorded around 1970, it was 17,500 in 1998.

literature

Web links

Commons : Mantled Gull  - Album with pictures, videos and audio files

Individual evidence

  1. ↑ a b c d BirdLife Species technical sheet, see web links
  2. ↑ Olsen / Larsson (2003), p. 128, see literature
  3. ↑ a b c d Olsen / Larsson, p. 128f (with tables), see literature
  4. ↑ Glutz von Blotzheim, p. 676f, see literature
  5. ↑ Olsen / Larsson, p. 135, see literature
  6. ↑ C. Sudfeldt, R. Dröschmeister, W. Frederking, K. Gedeon, B. Gerlach, C. Grüneberg, J. Karthäuser, T. Langgemach, B. Schuster, S. Trautmann, J. Wahl: Vögel in Deutschland - 2013 , DDA , LAG VSW, Münster 2013, p. 52
  7. ↑ a b c d Glutz von Blotzheim, p. 679f, see literature
  8. ↑ Olsen / Larsson (2003), p. 129, see literature
  9. ↑ Main call: audio sample
  10. ↑ Jauchzen (long call) audio sample
  11. ↑ a b Good (1998), section Sounds , see literature
  12. ↑ Stakkatoruf audio sample
  13. ↑ a b Glutz von Blotzheim, p. 681f, see literature
  14. ↑ Good (1998), section Distribution , see literature
  15. ↑ a b c d Olsen / Larsson (2003), p. 136, see literature
  16. ↑ a b c d Glutz von Blotzheim, pp. 683f, see literature
  17. ↑ Good (1998), section Migration , see literature
  18. ↑ a b c Glutz von Blotzheim, p. 690f, see literature
  19. ↑ a b Good (1998), Habitat section , see literature
  20. ↑ a b Del Hoyo et al. (1996), see literature
  21. ↑ Glutz von Blotzheim, pp. 697f, see literature
  22. ↑ a b c d Glutz von Blotzheim, p. 694f, see literature
  23. ↑ a b c Good (1998), section Food Habits , see literature
  24. ↑ a b c d e f Glutz von Blotzheim, p. 692f, see literature
  25. ↑ a b c d Good (1998), section Breeding , see literature
  26. ↑ Hüppop, K & O. Hüppop: Atlas for bird ringing on Helgoland, Vogelwarte 47 (2009), page 214
  27. ↑ a b List in Good (1998), section Demography and Populations , see literature
  28. ↑ a b c Glutz von Blotzheim, pp. 682f, see literature
  29. ^ A b Mikael Kilpi: Great Black-backed Gull in Ward JM Hagemeijer, Michael J. Blair: The EBCC Atlas of European Breeding Birds - their distribution and abundance , T & AD Poyser, London 1997, ISBN 0-85661-091-7 , Pp. 344-345
  30. ↑ Gedeon, K., Grüneberg, C., Mitschke, A., Sudfeldt, C., Eikhorst, W., Fischer, S., Flade, M., Frick, S., Geiersberger, I., Knoop, B. , Kramer, M., Krüger, T., Roth, N., Ryslavy, T., Stübing, S., Sudmann, SR, Steffens, R., Vökler, F., Witt, K .: Atlas of German breeding bird species. Atlas of German Breeding Birds . Vogelmonitoring Foundation Germany and umbrella association of German avifaunists, Münster 2014, ISBN 978-3-9815543-3-5 , p. 284 f .