Dunlin
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Dunlin ( Calidris alpina ), magnificent dress |
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| Calidris alpina | ||||||||||
| ( Linnaeus , 1758) |
The dunlin ( Calidris alpina ) is a circumpolar bird species from the family of snipe birds (Scolopacidae). A distinction is made between six and sometimes even ten subspecies, which form three genetically clearly differentiated subspecies groups, one of which is distributed in Europe, Siberia and Alaska as well as Canada.
The dunlin is a breeding bird on arctic tundras . However, he spends three quarters of his life on the train or in the wintering areas. In Central Europe it can be observed especially during the autumn migration on the coasts and wetlands. The somewhat misleading name dunlin is probably due to the fact that German-speaking ornithologists knew it at the beginning of the 19th century primarily as a breeding bird in the Lappish Alps .
description
The dunlin measures 17 to 21 centimeters and is therefore about the size of a star. The wingspan is about 32 to 36 centimeters. The bird weighs 40 to 60 grams and can live up to 24 years. The long, black beak is slightly bent downwards in the front quarter. The iris is brown-black. The barrel and toes are blackish olive.
Brood plumage
In the breeding dress, the crown feathers are dark brown to blackish with a reddish brown border in both sexes. Females have a brownish to brown neck. In males, however, this area can be almost light gray. The head sides are very variable in color. Some individuals have whitish head sides, while others are finely striped brown. In females, the sides of the head are often brown in color.
The back feathers are dark gray to black. The feathers on the back have broad, reddish-yellow to reddish-brown hems. Throat and chest are whitish with fine brown-black vertical stripes. The whitish flanks are dense dark brown mottled. The belly is black. The hand wings are matt dark brown, the arm wings are dark brown to gray and have a white border at the tip. The dark brown to gray-brown hand covers also have white lace hems. The large arm covers, the middle and the small covers are dark brown to blackish.
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Resting dress
A sexual dimorphism can no longer be determined in the resting dress . The upper side of the body is gray-brown to smoky gray in both sexes. Reddish to reddish brown borders are missing. Due to the dark spring shafts, the crown and the front back in particular appear finely dashed. The throat and chin are whitish. The neck is also whitish, but has a more or less distinct brown longitudinal line. The front breast is gray-brown with noticeably dark shaft stripes. The chest and belly are white.
Mauser
The moult of the dunlin usually takes place in low-disturbance and nutrient-rich moulting sites. Depending on the geographical location of the breeding area, the moulting area is still in the breeding area or in the wintering area. At rest areas such as the Baltic coast near Gdańsk , where dunlins gather for a few days during their migration, however, dunlins that are in active moulting are also caught again and again. From this it is concluded that dunlins also pull at least short distances during the moult and sometimes moult their inner hand wings before reaching the wintering place.
Fledglings
The downy cubs are white on the underside of the body and yellowish beige on the chest. The sides of the head are yellowish beige, with the cheeks being a little lighter. The skull and the top of the body are patterned yellowish brown and blackish brown. The dark back is finely dotted. A black stripe runs from the top of the beak to the top of the head. The reins and beard are very narrow, the neck is dark. The beak is black, the legs and toes are grayish pink, and the claws are dark gray.
Young birds change into their first resting plumage for the first time towards the end of summer. Some of them have mixed plumage until the end of November.
Possible confusion
In its splendid dress , the Dunlin cannot be confused with any other species due to its black belly spot. Because of its relative frequency, it is often used as a benchmark for identifying other waders. In the plain dress , if the black belly spot is missing, there is a possibility of confusion with the Baird sandpiper .
distribution
The dunlin is distributed in a circumpolar manner from the northern edge of the temperate latitudes to the arctic tundras. Breeding areas can be found in eastern Greenland, among others, while it is relatively rare on the west coast. It is also a breeding bird in Iceland, Jan Mayen and Svalbard . It breeds in Scandinavia, Russia from Kola via Novaya Zemlya to the Chukchi Peninsula , on the New Siberian Islands and Wrangel Island, in the west and north of Alaska and in the Canadian north west of Hudson Bay and on Southampton Island .
The winter quarters are mainly found on the coasts of the northern hemisphere. In addition to the coasts from northwestern Europe to west Africa, the wintering areas also include the Mediterranean and the southern coasts of Asia. It is comparatively seldom to be observed inland. During migration, it occurs in large numbers on many Central European coasts and in the Wadden Sea . The dunlins to be observed in Central Europe belong to three subspecies, the breeding areas of which are in northeastern Greenland, in northern Scandinavia and in northern Russia ( C. a. Alpina , C. a. Arctica and C. a. Schinzii ). In addition to the North Sea coast, important concentration points in the winter half-year are the coasts of Great Britain and Ireland, the Atlantic coast of France and West Africa to Mauritania. The dunlin uses different migratory routes depending on the distribution. For example, the dunlins who breed in Greenland migrate to West Africa via Iceland, Great Britain and Ireland. The breeding birds of Siberia can be found either in the Baltic or North Sea region and overwinter in an area that extends from the Netherlands to Great Britain and Ireland or they migrate via Russia and Ukraine to the Black Sea region and the Middle East.
habitat
The Dunlin prefers mud flats , moors , heathlands , tundras and salt marshes with low vegetation as their habitat . However, it is strictly linked to the presence of wetlands and open water. So the density of settlements in the tundra is lower, the drier it is.
The few Central European breeding birds breed on short grassy meadows directly on the coasts of the North and Baltic Seas and in their immediate hinterland. The meadows used are mostly salt meadows and pastures. Essential for the settlement of salt marshes by dunlins is a mosaic of large areas of very short-grass vegetation with covering bushes or tufts of higher grasses and herbs as well as deeper, bare and possibly muddy ground or open tides. A typical Central European breeding area for the dunlin is the island of Kirr of the Darß-Zingster lagoon chain , which is only 28 to 35 centimeters above sea level. With north-easterly winds, the meadows below are flooded over a large area. The more extensive water or silt areas as well as the somewhat drier areas, which are largely overgrown with salt marsh red fescue , offer the dunlin suitable breeding and feeding areas.
In southern Sweden, the dunlin mostly breeds on intensely grazed coastal meadows. Grazing keeps the vegetation low so that it can move around easily. In northern Iceland the Dunlin breed mainly in heather habitats and on lava fields that are grazed by sheep. However, the most important habitat of the dunlin is the tundra. On the banks of the rivers there are moist meadows with ponds, peat bogs and moss-sedge meadows. Dunlin prefer to breed on small elevations in the wet peat bogs. In Lapland it is preferred regions with dwarf birch, dwarf willow, hermaphrodite crowberry , blueberry and juniper , as well as sedge swamps, which serve as breeding habitats for the dunlin. On the Norwegian Hardangervidda the dunlin breed in the middle alpine zone at altitudes of 1350 above sea level. Here, too, the landscape is characterized by a diverse mosaic of dry and wet areas with low vegetation. In the northernmost part of its breeding area, the species breeds in the lichen tundra, where it has more humid places. However, the breeding population is higher in the so-called peat hill tundra, a typical tundra form in the south of the subarctic . Here, three to five meters high and 20 to 25 meters long peat hills, overgrown with moss, lichen and dwarf shrubs, alternate with moors filled with bogs or water. In addition to the dunlin, the crescent sandpiper , treadmill and spur bunting also breed here . In northern Alaska, the dunlin breed predominantly in the flat and moist tundra near the coast.
nutrition
The dunlin feeds on insects and their larvae , which it pecks out of the shallow water with its beak . At migration time, snails , worms and small crustaceans are also on his menu. In the tundras and coastal wet meadows, larvae and adults of gnats and mosquitoes provide the main food.
In their development, young birds are particularly dependent on insect food that is easy to capture and available even in bad weather. Especially in bad weather, the chicks are dependent on sufficient, high-energy food, as their downs are not waterproof and they cannot yet poke the ground with their beak. They peck the smallest animals from plants and soil. The chicks hatch on the tundra in July and thus during a period in which a maximum of such insects can be reached on the surface of the tundra.
Reproduction
The sexual maturity occurs after one year. The nest is cup-shaped and usually well hidden in a grassy forest. The female lays up to four eggs during the breeding season from April to July . The laying interval is 30 to 36 hours. The eggs have a smooth shell with a slight sheen. They are light to light olive, greenish or blue-green and have brownish blobs, spots and speckles. Both parent birds breed. The chicks hatch after about three weeks . After a further three weeks, the young birds have fledged.
Duration
Current inventory
The European breeding population was estimated at 350,000 to 570,000 breeding pairs at the beginning of the 21st century. The majority of them, namely 200,000 to 300,000 breeding pairs, breed on Iceland, they belong to the subspecies Calidris alpina schinzii . 15,000 to 130,000 breeding pairs belonging to the subspecies C. a. alpina , breed in the European part of Russia. There are also large populations in Greenland (7,000 to 15,000 breeding pairs), Norway (30,000 to 40,000 breeding pairs), Sweden (30,000 to 50,000 breeding pairs) and Great Britain (18,000 to 35,000 breeding pairs). The Central European brood population is very small. At the beginning of the 21st century, fewer than forty breeding pairs were breeding in Germany; in Poland there were between 10 and 20 breeding pairs. There are up to seven breeding pairs in Belgium and the Netherlands. In 2012 there was only one breeding site with four breeding pairs in Germany on the island of Kirr in Western Pomerania. In 2017, this tiny population consisted of eight breeding pairs.
Inventory forecast
The dunlin is one of the species for which a significant loss of area is predicted as a result of global warming. A research team that, on behalf of the British environmental authority and the RSPB, examined the future development of the distribution of European breeding birds on the basis of climate models assumes that large parts of the current distribution area will no longer meet the habitat requirements of this species by the end of the century. This applies in particular to Ireland, England, the south and east of Fennos Scandinavia , the Baltic States and northern Russia. The Central European brood population is also forecast to die out. Even if parts of Franz-Josef-Land , Spitzbergen and Nowaja Zemlya can offer the species new habitat due to climate changes, according to these prognoses the future distribution area corresponds to only 56 percent of today's.
The 2015 Red List of Germany's breeding birds lists the species in Category 1 as critically endangered.
literature
- Hans-Günther Bauer, Einhard Bezzel , Wolfgang Fiedler (eds.): The compendium of birds in Central Europe: Everything about biology, endangerment and protection. Volume 1: Nonpasseriformes - non-sparrow birds. Aula-Verlag Wiebelsheim, Wiesbaden 2005, ISBN 3-89104-647-2 .
- Collin Harrison, Peter Castell: Fledglings, Eggs and Nests of Birds in Europe, North Africa and the Middle East. Aula Verlag, Wiebelsheim 2004, ISBN 3-89104-685-5 .
- Richard Sale: A Complete Guide to Arctic Wildlife. Christopher Helm Publisher, London 2006, ISBN 0-7136-7039-8 .
- Arnd Stiefel, Horst Scheufler: The Dunlin. Die Neue Brehm-Bücherei, A. Ziemsen Verlag, Wittenberg Lutherstadt 1989, ISBN 3-7403-0160-0 .
Web links
- Videos, photos and sound recordings for Calidris alpina in the Internet Bird Collection
- Calidris alpina in the endangered Red List species the IUCN 2008. Posted by: BirdLife International, 2008. Accessed on December 19 of 2008.
- J. Blasco-Zumeta and G.-M. Heinze: Age and gender characteristics of Spanish migrants (PDF; 1.6 MB) (Engl.)
- Dunlin's feathers
Individual evidence
- ↑ a b c Bauer et al., P. 541.
- ↑ Stiefel et al., P. 107.
- ↑ Stiefel et al., P. 12.
- ↑ a b Harrison et al., P. 136.
- ↑ Harrison et al., P. 137.
- ↑ a b Sale, p. 181.
- ^ Sale, p. 181 and p. 182.
- ↑ a b c Bauer et al., P. 542.
- ↑ Stiefel et al., P. 113.
- ↑ Martin Flade: The breeding bird communities of Central and Northern Germany - Basics for the use of ornithological data in landscape planning. IHW-Verlag, Berlin 1994, ISBN 3-930167-00-X , p. 542.
- ↑ Stiefel et al., P. 107 and p. 108.
- ↑ Stiefel et al., P. 109.
- ↑ Stiefel et al., P. 112.
- ↑ Stiefel et al., P. 119.
- ↑ Christof Herrmann, Marie Junge: The breeding stocks of coastal birds in the protected areas of Mecklenburg-Western Pomerania 2001–2012. Seevögel 2013/34, no. 3, pp. 86–148.
- ↑ Vorpommersche Boddenlandschaft National Park : Insel Kirr , accessed July 29, 2017.
- ^ Brian Huntley, Rhys E. Green, Yvonne C. Collingham, Stephen G. Willis: A Climatic Atlas of European Breeding Birds. Durham University, The RSPB and Lynx Editions, Barcelona 2007, ISBN 978-84-96553-14-9 , p. 183.
- ↑ Christoph Grüneberg, Hans-Günther Bauer, Heiko Haupt, Ommo Hüppop, Torsten Ryslavy, Peter Südbeck: Red List of Germany's Breeding Birds , 5 version . In: German Council for Bird Protection (Hrsg.): Reports on bird protection . tape 52 , November 30, 2015.