Velvet duck
| Velvet duck | ||||||||||||
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Male velvet duck ( Melanitta fusca ) in magnificent dress |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Melanitta fusca | ||||||||||||
| ( Linnaeus , 1758) |
The velvet duck ( Melanitta fusca ) is a sea duck in the duck bird family that is found in both Eurasia and North America. A total of three subspecies are distinguished, which in the males differ mainly in the shape of the eye spot. In females, however, the shape of the beak and the position of the feather tips on the beak vary. In Eurasia, both the summer and winter locations overlap with the very similar looking common scoter ( Melanitta nigra ).
In Central Europe, the velvet duck is a frequent migrant and winter visitor on the North and Baltic Sea coasts. Inland it can be observed more regularly and more frequently than the common scoter . In the coastal area there are also some over-summerers.
Features and voice
The velvet duck has a body length of 51 to 58 centimeters. On average, the males weigh around 1.5 kilograms, while the females weigh a little less than 1.2 kilograms on average.
The male is black and has a white spot under the eye. The base of the upper beak is thickened and has an orange field. The feet are red. Compared to the common scoter, the males of the velvet duck are slightly larger and more compact. The duck's beak is also longer. In the male, the beak has a larger orange-colored section and an orange-pink nail. The base of the beak is slightly swollen. Unlike the male scoter, velvet ducks do not have a hump on their beak. The irises of the males are blue-gray.
The female is feathery brown and has a white spot between the eyes and beak. The iris is darker in the females than in the males. Both sexes have a white mirror on the edge of the wing.
In flight, the velvet duck differs from the similar looking scoter and spectacled ducks by its white mirror. Basically, this duck is also a little more trusting than the common scoter, which flies open very quickly when ships or boats approach.
voice
The velvet duck is usually a very calm bird. During the breeding season, the male can occasionally hear a huör-är or an ohjo .
Distribution and existence of the three subspecies
The velvet duck inhabits the northern areas of Europe , Asia and North America . Apart from the south of Norway and Sweden, Scandinavia is one of their breeding areas. It is also found in the Baltic Sea and breeds in the archipelago, among others. It is most common in Fennoscandinavia at an altitude of over 500 meters. There are 3.4 breeding pairs per 100 square kilometers. However, the number of Scandinavian breeding birds has continuously decreased in the 20th century. However, Norway is still an important moulting area for this species. In 1985, 10,600 velvet ducks were counted here, which moulted in Norwegian and Danish waters.
The velvet duck is also a breeding bird of Russia. The nominate form of the three subspecies occurs in an easterly direction at least as far as the Yenisei ; Statements that it also breeds east of Chatanga are not considered to be sufficiently proven. In Russia, their breeding area extends very far to the south and also reaches afforested steppe. Isolated breeding populations with a very disjoint distribution area can also be found in Turkey, Armenia, Georgia and Turkmenistan. The number of these birds is estimated to be less than 10,000, they overwinter mainly in the Caspian Sea.
The other European breeding birds of the nominate form overwinter mainly in the coastal areas of north-western Europe. Only a small part of the population is found off the coast of Murmansk and in northern Norway during the winter months. The velvet duck overwinters in significant numbers in the Baltic Sea, at the beginning of the 1990s the winter population was estimated at 933,000 individuals [Source4]. The largest wintering area is the Pomeranian Bay (DE, PL) including the Greifswalder Bodden (DE). Large stocks are also found in the Riga Bay (LV), the Irbe Strait (EE, LV) and in front of the Curonian Spit (LT, RU), smaller ones everywhere in the southern and western Baltic Sea. Therefore, during the spring, large flocks of velvet ducks can be observed moving back to their breeding grounds. In 1997, 386,000 velvet ducks were counted flying over Estonia and another 60,000 crossing the Gulf of Finland.
The subspecies Melanitta fusca stejnegeri is common in East Asia . Its range begins on the Yenisey River and occurs from there in an easterly direction to Sakhalin and the Kurilskiye Archipelago that lies between Kamchatka and Japan. Most often it can be seen on the Lena . Here, however, the population fell sharply, especially in the 1970s. Reliable population figures are very difficult to determine for this subspecies. The stock is estimated to be between 600,000 and 1,000,000.
In North America, the subspecies Melanitta fusca deglandi occurs, which breeds from North Dakota, Manitoba, Saskatchewan and Alberta. It reaches its highest breeding density in the Northwest Territories, where it can be observed from the north shore of the Great Lakes to the Arctic coast of Canada. The International Ornithologist's Union leads the subspecies Melanitta fusca deglandi due to a publication by Bradley Curtis Livezey as a separate species Melanitta deglandi .
The total number of North American velvet ducks is estimated at 1 million birds. Their population is considered stable.
habitat
The velvet duck is a breeding bird in the boreal coniferous forests and on mountain lakes. It occasionally breeds inland in the archipelago and along the forested coastline of the Baltic Sea coast. During its migrations to the wintering areas and back to the breeding areas in spring, it occasionally spends time on freshwater lakes. Most of them, however, overwinter in the coastal waters.
Reproduction
Pairs are found in late winter and spring, so that the velvet duck usually arrives in the breeding areas paired. Velvet ducks have a group courtship, in which several males flock around several females. The courtship ritual includes the males diving down, in which they approach the females underwater. Mated females show a noticeable flight behavior in the morning by flying low over land, shouting loudly and returning to their starting point. This behavior is shown up to the beginning of the oviposition. The couples only defend a small area around the nest. The pair bond already subsides while the female is still brooding. The males then already move to their moulting sites.
The nest is built on the ground near lakes, rivers, or the seashore. In the taiga it is not more than 100 meters from the nearest open body of water. Occasionally these ducks also nest in colonies of gulls.
The female only lays one clutch. The number of eggs varies depending on the subspecies. In the nominate form, the clutch size is usually seven to nine eggs. The eggs are oval in shape and creamy white. Newly hatched dune young weigh around 54 grams.
food
The velvet duck searches for its food exclusively by diving, whereby it remains under water for 1 minute and can dive up to 10 meters deep. It mainly feeds on crustaceans and molluscs.
Especially in winter it has been observed that velvet ducks sometimes go looking for food together with red-necked grebes , especially over sandy bottom. Presumably, during these dives, mainly poly-bristles are scared off (on average> 1000 per square meter) and ingested by both species.
Duration
The IUCN classifies the velvet duck as harmless ( least concern ), as the range is very large. Basically, population numbers are expected to decrease, but the population decline has not yet reached the critical limit at which a species is included in the IUCN's early warning levels. The population is estimated at 1.7 to 3 million sexually mature individuals.
literature
- 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 .
- John Gooders and Trevor Boyer: Ducks of Britain and the Northern Hemisphere , Dragon's World Ltd, Surrey 1986, ISBN 1-85028-022-3
- Janet Kear (Ed.): Ducks, Geese and Swans. Oxford University Press, 2005, ISBN 0-19-854645-9 .
- Hartmut Kolbe; Die Entenvögel der Welt , Ulmer Verlag 1999, ISBN 3-8001-7442-1
- Richard Sale: A Complete Guide to Arctic Wildlife , published by Christopher Helm, London 2006, ISBN 0-7136-7039-8
Web links
- Melanitta fusca in the endangered Red List species the IUCN 2008. Posted by: BirdLife International, 2008. Accessed January 31 of 2009.
- BirdLife factsheet for the velvet duck
- Velvet duck feathers
Individual evidence
- ↑ Gooders and Boyer, p. 135
- ↑ Bauer et al., P. 133
- ↑ a b Kear, p. 715
- ↑ Sale, p. 129
- ↑ Hans-Heiner Bergmann; Hans-Wolfgang Helb; Sabine Baumann; The voices of the birds of Europe - 474 bird portraits with 914 calls and chants on 2,200 sonograms , Aula-Verlag, Wiesbaden 2008, ISBN 978-3-89104-710-1 , p. 70
- ↑ a b Kear, p. 716
- ↑ a b Kear, p. 717
- ↑ The Condor, Volume 97, Number 1, 1995, pp. 233-255 Phylogeny and Evolutionary Ecology of Modern Seaducks (Anatidae: Mergini) (English; PDF; 1.9 MB)
- ↑ a b c Kear, p. 718
- ↑ Ingvar Byrkjedal, Steinar Eldoy, Svein Grundetjern, Mass K. Loyning: Feeding associations between Red-necked Grebes Podiceps griseigena and Velvet Scoters Melanitta fusca in winter . In: Ibis , Vol. 139, No. 1, January 1997, pp. 45-50, doi : 10.1111 / j.1474-919X.1997.tb04503.x .
- ↑ BirdLife Factsheet on the Velvet Duck , accessed December 14, 2010