Mountain duck
| Mountain duck | ||||||||||||
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Mountain Duck ♂ ( Aythya marila ) |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Aythya marila | ||||||||||||
| ( Linnaeus , 1761) |
The mountain duck ( Aythya marila ) is a duck belonging to the genus group of diving ducks , which can be found in the two subspecies A. m. marila and A. m. mariloides occurs. It is almost circumpolar in the coniferous forest zone and partly also in the subarctic Strauchtundra and thus the northern counterpart to the Old World tufted duck and the New World violet duck .
In Central Europe the mountain duck is only a sporadic or local breeding bird and summer visitor. It can be seen much more often as a pull-through and winter visitor in northern Central Europe. In inland it occurs only locally or sporadically during this period.
features
Characteristics of adult scallop
Scallops are medium-sized diving ducks. When fully grown, they reach a body length of 40 to 51 centimeters. They weigh on average just under 1.2 kilograms.
Scallops are similar to tufted ducks , but have no feathers and a gray back. The head plumage shines slightly green. In some individuals, this shimmer can even appear purple. The division of body color - black neck and chest, white sides and dark tail - is similar to that of the tufted duck. The most striking difference to the tufted duck is the light silver-gray back in the front area. Towards the tail it becomes increasingly dark gray. The beak is a light lead gray. When resting, the male largely resembles the female.
The female is brown and is very pale at the base of the beak. It resembles the female of the tufted duck in its entire body. The most reliable distinguishing feature from the tufted duck is a white band that surrounds the beak root and is usually much larger than is found in female tufted ducks. In some individuals, however, it is only formed as a narrow white border and occurs in a similarly narrow form in some female tufted ducks. In addition, female mountain ducks are grayer on their backs than female tufted ducks, and they have no forelock. A broad white wing stripe can be seen in flight. Scallops are rarely seen on land.
The moulting process is similar to that of the tufted duck. The adult females change their body plumage around March. The moulting of the swinging feathers takes place in the middle of the summer or in the late summer. The tail feathers are moulted from April to September. A partial change of the body plumage takes place in August to November. In the male, moulting takes place later. The change to the resting dress begins towards the end of May and usually ends at the beginning of July. The rocker feathers are thrown off almost simultaneously, so that they are flightless for about three to four weeks from June to September.
The voice of the mountain ducks can only be heard during courtship time. During this time, the male calls out a very quiet and nasal weiar or faster wik-wik-wiu . The sounds during courtship also include a soft, cooing kuku .
Characteristics of the chicks and fledglings
Similar to the tufted duck, the chicks of the scallop are predominantly black-brown. Some chicks have yellow-brown spots on the wings and sides of the body. The chest and belly are cream to yellowish in color. The upper breast is reddish brown. The throat is also yellowish. They have diffuse, dark eyebrows on their faces.
The iris of newly hatched chicks is gray-blue. The upper beak is black-brown with a brown nail. The lower bill is flesh-colored. The legs, feet and webbed feet are dark gray. In the growing scallop, the iris changes color to yellow. This change in color is completed shortly before the young ducks fledge. The beak is gray-blue at this point. Young birds have a plumage that is largely similar to the females. With them, however, the white ring at the base of the beak is always only slightly developed, and their cheeks, front neck and sides of the neck are paler. The young birds do not show the full plumage of adult scupper until they are two years old.
Possible confusion with other ducks
The scallop is very similar to the tufted duck and the North American violet duck . The tufted duck is smaller, less massive in body and has a more rounded back. In contrast, the back of a swimming scallop is mostly flat. Tufted ducks also lie higher up in the water. The main distinguishing feature is the black back of the tufted duck, which is not always clearly visible when observing the field.
The possibility of confusion between scallop and violet duck is particularly great, as these species have almost identical body plumage. The breeding area of these two species overlap in Alaska and northern Canada. They also use similar wintering areas on the coast of North America. One of the distinguishing features is that the fine, dark streaking of the violet duck is somewhat more intense, so that its back plumage appears somewhat darker overall. Their flanks are also grayer. The big problem of reliably differentiating these two species makes it particularly difficult to give stock figures for this species.
distribution
Scallops are circumpolar in the north . The breeding areas of the subspecies A. m. marila stretch from Scandinavia to the Lena in Siberia . The rest of Siberia and all of North America are made up of the somewhat smaller subspecies A. m. colonized by mariloides . The closed breeding area extends from Iceland across the Hebrides and the far north of Scotland to Scandinavia, Norway, Finland and Lapland. The breeding area extends from Murmansk and the White Sea coast to northern Siberia. Scallops also breed on the Sakhalin Peninsula.
In rare cases one finds broods in Central Europe , for example in Schleswig-Holstein , in the USA at least as far as Ortenville , Minnesota . There, on April 12, 1948, four animals were observed killing seven leopard frogs.
Scallops leave their breeding grounds to overwinter. A small number of Scallops overwinter in southwest Iceland and southern Alaska. The rest of the population, however, spends the winter on the milder coasts in the east and west. The main European wintering quarters include the south-west of the Baltic Sea, the North Sea coast, the coastal waters of southern Norway, Great Britain and Ireland and the north-west of France. Breeding birds from Siberia overwinter partly on the northern and western coast of the Black Sea area and in the Caspis Depression. The scupper then prefer to stay in shallow straits or bays. The main criterion for the selection of winter quarters is an adequate supply of feed. A large number of scallops overwinter in the Firth of Forth , as there are numerous mussels here. North American populations overwinter on the coast of the Pacific and Atlantic, as well as on the Mississippi and Missouri. In Asia, there are wintering quarters on the coasts of Korea and China as well as Taiwan. About 170,000 scupper ducks can be found on the coasts of Japan in winter.
Scaling ducks can be seen in Central Europe from September onwards. In mild winters, the withdrawal from winter quarters begins as early as February, otherwise in mid-March. In the Baltic Sea area, the peak of the withdrawal is in April. Tufted ducks do not arrive at their northernmost breeding sites until mid-May.
Habitat and way of life
Scallops live by lakes and ponds in the tundra and forest tundra during the summer . Subalpine waters and raised bogs are also part of their range. The animals spend the winter months along the coasts of the temperate latitudes . It prefers sheltered, quiet sections of the coast and often stays in estuaries. Where it winters inland, it prefers stagnant water to flowing water.
Scallops breed by the water on the ground. Breeding begins in May, ends in July and lasts for 24 to 25 or 28 days, depending on the subspecies. The young can fledge after about 50 days.
food
Scallops feed mainly on animal food, especially mussels , snails and frogs, but to a lesser extent also on seeds, sprouts and leaves of aquatic plants . Vegetable food is particularly consumed in spring and summer. Seeds play a bigger role in their diet than leaves and sprouts. Downy young mostly eat animal food. They catch insects with their beak or pick them up from the surface of the water.
Reproduction
Scallops begin their courtship in their winter quarters. However, the peak of courtship is only reached when the animals have returned to the breeding area. This is also where pairing takes place for the majority of the population. The return to the breeding area occurs from mid-April. However, the majority of the population does not arrive there until the beginning of May.
Tufted ducks prefer to breed near bodies of water in open swamp or tundra landscapes. The nests are built in the bank area and are mostly in the sedge and rush stands. Scallops prefer to breed on islands and then breed densely like colonies. In some regions of their breeding area, their nests are found in colonies of gulls and terns. Scallops only raise one clutch a year.
A single clutch usually consists of six to nine eggs. They are light brown to olive gray in color and long-oval with a size of 63.2 × 43.5 millimeters. The females begin to lay eggs in the southern breeding area from the end of May. In the north, breeding begins in early June. The female breeds alone. The drakes stay in the vicinity of the nest and the female until the second half of the brood and also spend the time when they leave the nest to take up food with the female. The dune young hatch after a period of 26 to 28 days. They fledge after five to six weeks.
Duration
In north-western Europe, a total of around 310,000 scupper ducks overwinter. The wintering population on the Black Sea, Caspian Sea and Mediterranean Sea is estimated at around 200,000 Scupper. The North American population, which is very difficult to determine exactly due to the possibility of confusion with the violet duck, is assumed to be around 750,000 scallop. In addition, there are around 200,000 and 400,000 scavenger ducks that breed in northern East Asia.
Long-term changes in stocks are hardly recognizable in the European breeding populations. Larger losses are caused by drowning in fishing nets, a problem that occurs especially in the IJsselmeer . Oil spills represent a further danger for this species. The concentration of this species on a few large resting and winter areas is also to be viewed critically, since these locations are often not legally protected locations and this species of duck is hunted. In Germany the mountain duck is classified as a type of responsibility within the federal government's national strategy for biological diversity. The hunting season is set from October 1st to January 15th by the Federal Hunting Act. With the exception of Bavaria , Bremen , Saxony and Saxony-Anhalt, Scallops are spared nationwide all year round . In Switzerland and Austria, the mountain duck is not one of the hunted duck species.
Eponyms
The asteroid (8438) Marila is named after Aythya marila .
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 0198546459 .
- Erich Rutschke: The wild ducks of Europe - biology, ecology, behavior , Aula Verlag, Wiesbaden 1988, ISBN 3-89104-449-6
Web links
- More photos and information
- Aythya marila in the endangered Red List species the IUCN 2008. Posted by: BirdLife International, 2008. Accessed on December 18 of 2008.
- Videos, photos and sound recordings of Aythya marila in the Internet Bird Collection
- Feathers of the scallop
Individual evidence
- ↑ a b c Kear, p. 676.
- ^ Kear, p. 675.
- ↑ 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. 65.
- ↑ Collin Harrison and Peter Castell: Field Guide Bird Nests, Eggs and Nestlings , HarperCollins Publisher, revised edition from 2002, ISBN 0007130392 , p. 76.
- ↑ a b c Kear, p. 677.
- ↑ Rutschke, p. 274.
- ↑ a b nature + cosmos (2008-03).
- ↑ a b Bauer et al., P. 118.
- ↑ Gooders and Boyer, pp. 102-104.
- ↑ Rutschke, p. 275.
- ↑ a b Rutschke, p. 276.
- ↑ a b Collin Harrison and Peter Castell: Field Guide Bird Nests, Eggs and Nestlings , HarperCollins Publisher, revised edition from 2002, ISBN 0007130392 , p. 75.
- ↑ Bauer et al., P. 118 and p. 119.
- ↑ 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
- ↑ MPC
