Dwarf swan
| Dwarf swan | ||||||||||||
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Little swan ( Cygnus bewickii ) |
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| Scientific name | ||||||||||||
| Cygnus bewickii | ||||||||||||
| Yarrell , 1830 |
The dwarf swan ( Cygnus bewickii ) is a bird art from the genus of swans ( Cygnus ), and the family of the Anatidae (Anatidae). The dwarf swan occurs in a similar habitat as the whooper swan . It is one of those swans that breed relatively often in loose, colony-like associations.
Sometimes the Tundra Swan is also called subspecies Cygnus columbianus bewickii to in North America occurring tundra swan found.
In Central Europe, the dwarf swan is an annual winter visitor. Most of the individuals are observed in the Netherlands.
Appearance
With a length of 115 to 140 centimeters and a weight of 3.4–7.8 kilograms, the dwarf swan is the smallest of the European swans. Its appearance is similar to the Whooper Swan ( Cygnus cygnus ), with completely white plumage, black legs and a yellow beak base. But it is smaller, shorter-necked and has a more rounded head shape. It is characteristic of this species that they usually carry their necks upright. The beak is colored too black towards the tip. The color pattern on the beak is individually different. In contrast to the whooper swan, the black part of the beak always outweighs the yellow part. The tail is short and rounded.
The downy chicks are pale gray-white. The underside of the body is pure white. They are very similar to whooper swans' dune chicks. At the time of hatching, their beak is pink. The tip of the beak is gray with a black nail. Feet, legs and webbed feet are orange to pink. With increasing days of life, the upper bill becomes pure pink with a dark beak tip. The legs, feet, and webbed feet turn gray-pink. They are only dark gray when the young birds have fledged.
voice
Similar to the whooper swan, the dwarf swan also has a trumpeting reputation. But it is louder, sounds more nasal and is usually higher in pitch. Before the flight they let out an intense, multisyllabic series of calls. This sounds either muffled hög hög ... or like a trumpeting hügögök . During the flight they emit single or persistently repeated calls with overtones. These can be onomatopoeically described as göök , klü , ong or as multi-syllable ang-ang-ang .
distribution
The dwarf swan breeds in the tundras of Eurasia , from the Kola Peninsula to around the mouth of the Kolyma River in eastern Siberia. The entire breeding area is thus in northern Russia . In autumn the birds migrate south across the White Sea and the Baltic Sea and winter on the German and Dutch North Sea coasts , in England and Ireland . Other groups of pygmy swans overwinter in the Caspian Sea , the Aral Sea and in East Asia . Through the creation of quarry ponds through the construction of the autobahn and rewetting, the Emsland has become an important wintering region, where the dwarf swan finds a rich food supply as a result of the intensive potato and corn cultivation. In Germany, the miniature swan is classified as a type of responsibility within the national strategy for biological diversity of the federal government.
habitat
The pygmy swan breeds in the arctic tundra in swampy terrain, especially in shallow and vegetation-rich still and flowing waters. In the wintering area it often stays near the coast and can then be found in the marsh , on flooded grassland near the coast or in cultivated land. During this time it is often associated with whooper swans.
Diet and Lifestyle
The pygmy swan feeds on aquatic plants and grasses . Initially, insects also play an important role in the chicks' diet . On the passage and in the winter quarters, crops left behind, such as potatoes and grains, are added to the food.
The birds dig for food from the bottom of shallow waters or graze on land. They are active both day and night.
Outside of the breeding season, the pygmy swans are very sociable. In contrast, they demarcate territories during the breeding period.
Reproduction
The birds mate for a lifetime at 3–4 years of age, but usually do not begin to breed until 5–6 years of age. The nest is built from parts of plants on a raised area. Mostly mosses and lichens are used. The shape of the nest is conical. Both parent birds are involved in building the nest. The egg-laying usually begins in the second week of June. The female lays 4–6 eggs . These are elliptical in shape and creamy white in color. Their surface is smooth and shimmers slightly. The female then incubates them for about a month. However, when the female leaves the clutch, the male adult bird occasionally perches on the nest.
The chicks usually hatch within 24 to 36 hours. They are fleeing nests who are cared for by both parent birds. They are fully fledged when they are around 40 to 45 days old. The young birds fledge after a further 7-10 weeks, but then stay with their parents for the entire winter.
literature
- Tobias Böckermann : On wide swings into the Emsland. More and more whooper swans and dwarf swans overwinter in western Lower Saxony . In: Studiengesellschaft für Emsländische Regionalgeschichte (Ed.): Emsländische Geschichte 16, ISSN 0947-8582 pp. 97–110.
- Hans-Heiner Bergmann / Hans-Wolfgang Helb / Sabine Baumann: The voices of Europe's birds - 474 bird portraits with 914 calls and chants on 2,200 sonograms . Aula-Verlag, Wiesbaden 2008, ISBN 978-3-89104-710-1 .
- Janet Kear (Ed.): Ducks, Geese and Swans . 2 volumes. Oxford University Press, Oxford 2005, ISBN 0-19-854645-9 , ( Bird families of the world 16).
- Josep del Hoyo et al .: Handbook of the Birds of the World. Volume 1: Ostrich to Ducks. Lynx Edicions, 1992, ISBN 84-87334-10-5 .
- Josep del Hoyo et al. (Ed.): Ostrich to ducks . Lynx Edicions, Barcelona 1992, ISBN 84-87334-10-5 , ( Handbook of the Birds of the World 1).
- Richard Sale: A Complete Guide to Arctic Wildlife , published by Christopher Helm, London 2006, ISBN 0-7136-7039-8
- Andreas Schüring: Heralds of the lost winter. Little swans and whooper swans. Guests from Siberia in Emsland . In: Yearbook of the Emsländischen Heimatbund 86, 2010, ISSN 0448-1410 , pp. 233-236.
Individual evidence
- ↑ Hans-Günther Bauer, Einhard Bezzel and 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 , p. 48
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↑ Collin JO Harrison / Peter Castell: Field Guide Bird Nests, Eggs and Nestlings. With North Africa and the Middle East . Reprint of the revised edition 2002. Harper Collins, London 2004, ISBN 0-00-713039-2 , p. 63.
(Also in German: Young birds, eggs and nests of the birds of Europe, North Africa and the Middle East . Aula-Verlag, Wiebelsheim, 2004, ISBN 3-89104-685-5 ). - ↑ Bergmann et al., P. 35
- ↑ Species under special responsibility in Germany ( Memento of the original dated August 2, 2017 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. on the homepage of the Federal Agency for Nature Conservation, accessed on June 3, 2016
Web links
- Videos about miniature swans in the Internet Bird Collection
- Feathers of the miniature swan