Marble duck
| Marble duck | ||||||||||
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Marmelente ( Marmaronetta angustirostris ) |
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| Systematics | ||||||||||
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| Scientific name of the genus | ||||||||||
| Marmaronetta | ||||||||||
| Reichenbach , 1853 | ||||||||||
| Scientific name of the species | ||||||||||
| Marmaronetta angustirostris | ||||||||||
| ( Ménétriés , 1832) |
The marbled duck ( Marmaronetta angustirostris ) is a species of bird in the duck family . Although this species moults its plumage twice a year according to current knowledge, the males do not show any splendor.
The marbled duck is the only species of the genus Marmaronetta . The genus occupies a special position between diving and swimming ducks and represents an independent, monotypical evolutionary line of ducks. The species, which is generally very rare, is considered to be endangered due to habitat loss . Their main breeding grounds included the Iraqi Ahwar swamps, which were systematically drained during the Anfal operation in the 1980s and 1990s. At the beginning of the 3rd millennium, the worldwide winter population of this species of duck was estimated at only 14,000 to 16,000 ducks.
In Central Europe, the species is a very rare stray visitor, although there were possibly breeding birds in Hungary in the 1890s. It is a migratory bird with a highly variable tendency to migrate, and in 1892 a large number of marbled ducks came into the Central European area. Today's individuals who are observed again and again in Central Europe are presumably exclusively refugees from prison.
features
Appearance of fully grown marbled ducks
Marbled ducks are a small species of duck. They reach a body length of 39 to 42 centimeters. They are only slightly larger than teal and weigh an average of about 540 grams. In terms of their habitus, they are reminiscent of gudgeon ducks , but according to their behavior the marbled duck can be classified as diving ducks .
One of the special features of these species is that there is no conspicuous sexual dimorphism. They also lack the wing mirrors that are characteristic of most other ducks. The plumage is light brown to a light gray brown. With the exception of the head, neck and front chest, their entire plumage is light cream, gray-white or dirty yellow. This is because the cream-colored feathers have dark gray-brown fringes. The underside of the body is banded. At the back of the head there are hood-like elongated feathers. In the female, this bonnet is less pronounced. The area around the eyes is dark. This dark eye spot can stretch to the nape of the neck. The tail is white. They have a long, narrow, black beak.
Marbled ducks have a uniform plumage all year round. However, the beak of the male shines during the breeding season. It will then have a narrow blue band behind the nail. The edges of the beak and the lower base of the upper beak are also blue. Outside the breeding season, this blue band fades to a pale gray.
The females are generally slightly smaller than the males. With them, the short profile looks rounder, since the spring hood is either smaller or even missing entirely. The beak is slightly shorter and the dark eye spot is less large. The headstock is also slightly lighter than that of the male. In females, the beak is dull black during the breeding season. At the base of the upper beak it has a differently large olive-green color. In non-breeding females this usually fades to a shade of gray.
voice
The calls of the marbled ducks are seldom heard. The males occasionally express a nasal jiib , ji- ü , kij or ch queije during courtship . A croaking, as is characteristic of the females of other duck species, cannot be heard from the female of the marbled duck.
Appearance of the chicks and fledglings
The back, the back of the neck and the head plate of the marbled duck chicks are gray-brown to dark sand-colored. There are light brown areas of color on the wings and flanks. The underside of the body and the sides of the head are cream-colored to yellowish white. The cheeks, chin and throat are light cinnamon in color. A brownish gray line of color runs from the base of the beak over the eye to the neck. On the middle back and the rump sides they each have two small light vertical stripes. With this appearance, the chicks are very similar to the chicks of mallards. However, their upper side is darker and the light colored areas are less clearly delineated. Mallard chicks are more yellowish than light cinnamon on their cheeks, chin and throat.
The upper bill is greenish gray in newly hatched chicks. The nail is brown. The lower bill, however, is flesh-colored. The legs and feet are olive gray while the webbed feet are brown. In growing marbled ducks, the bill changes color to a blue-gray or dark gray. The webbed feet also turn dark blue-gray.
Young marbled ducks are similar to adult marbled ducks. Their back plumage is, however, still rather uniformly dark and does not show the light spots of the adult ducks. The light drops on the edge of them merge into the darker feather parts. In their case, the dark eye spot is also not so pronounced. In young males, the blue band at the tip of the beak appears for the first time in the fifth month of life. In the young females, the gray spots develop on the base of the beak at the same time.
distribution
The marbled duck was once widespread around the Mediterranean and Central Asia. It was pushed back to relic occurrences in the post-ice age and has lost another large part of its habitat in modern times due to human interference. It is a breeding bird of the Mediterranean sub-region and therefore only occurs in the warmest and driest parts of the Palearctic . Today it occurs only in Andalusia and the Camargue as well as on Mallorca (Spain). There are also scattered deposits in parts of Tunisia and Morocco . In Central Asia, the marbled duck is widespread from Tajikistan and Uzbekistan to Northern Iran and Afghanistan . Marbled ducks observed in Central Europe are always captive refugees, as these ducks are popular park birds.
In southern Spain, North Africa, Turkey and on the shores of the Caspian Sea, the marbled duck is a resident bird. In the rest of the distribution area it migrates to Egypt, the Persian Gulf or winters in waters in Pakistan. The marbled ducks that breed in the west of the distribution area migrate in small numbers to Senegal and Lake Chad.
habitat
Marbled ducks breed in ponds, ponds and lakes rich in vegetation, both in fresh and brackish water . It can also be found in depressions containing soda and soda in semi-deserts, provided they have a belt of vegetation. The reason for the relative rarity of these ducks are their high demands on their habitat. Unlike many other duck species, the marbled duck does not move between resting or breeding grounds and feeding grounds. Instead, it resides in a single body of water that must meet all of its habitat requirements. It must be shallow and have a thick belt of reeds. These bodies of water are typically rich in food and are particularly popular with drainage in order to convert them into agricultural land.
food
The bird feeds on mainly insects and mollusks. Vegetable food only makes up a small proportion. The acquisition of food is done by rooting and diving.
Reproduction
The pairing takes place in winter. Marbled ducks are not territorial birds and breed in loose, colony-like associations. The nest is built well hidden on the densely overgrown bay. Occasionally it is also erected in burrows in the ground, similar to the shelduck . Several cases have been documented in which marbled ducks even nested in the thatched roofs of older houses and huts. The nest is usually located in the immediate vicinity of the water and is laid out with grasses and dunes. The nest dunes are medium gray with almost white centers and tips. The clutch usually consists of nine to thirteen eggs. However, clutches have also been found that contained only five or up to eighteen eggs.
As a heat-loving species, breeding begins relatively late. Birds nesting in Spain do not lay their eggs until May or early June. The female breeds alone. The incubation period is 25 to 27 days. The male leaves the female at the beginning of the breeding season to form loose swarms with other drakes. After hatching, the chicks are taken by the female to the shallow water zone near the reed and reared there.
Duration
The marble duck is a globally endangered species of bird. It is classified as endangered ( vulnerable ) by the IUCN . The main cause of the significant population decline is habitat loss. Around fifty percent of the breeding habitats were destroyed in the 20th century through the drainage of wetlands, hydraulic engineering, reed mowing or grazing and intensified agricultural use. The European breeding population is only 390 to 1,000 breeding pairs, the winter population is slightly higher with four hundred to 1,200 individuals.
After the Iraqi Ahwar swamps were rewetted, a count in the winter of 2010 showed 46,000 marbled ducks, roughly double the previously estimated total world population.
Keeping as ornamental poultry
The world's first breeding of jellyfish was achieved in a British zoo at the turn of the 20th century. During the first half of the 20th century only a few marbled ducks were kept worldwide. The British Wildfowl Trust imported several ducks from Iraq in 1948 and established successful conservation breeding with them. Animals from these offspring found their way into a number of European and North American zoos. In Europe, however, the number of marbled ducks kept declined in the 1980s, as zoos and private owners increasingly focused on other species.
supporting documents
Individual evidence
- ↑ Kear, p. 625
- ↑ Bauer et al., P. 83
- ↑ Kear, p. 626
- ↑ Bauer et al., P. 83
- ↑ Kear, p. 626
- ↑ Rutschke, p. 330 and p. 331
- ↑ Kear, p. 625
- ↑ 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. 54
- ↑ Kolbe, p. 262
- ↑ Kolbe, p. 262
- ↑ Kear, p. 625
- ↑ Collin Harrison and Peter Castell: Field Guide Bird Nests, Eggs and Nestlings , HarperCollins Publisher, revised edition from 2002, ISBN 0007130392 , p. 74
- ↑ Kear, p. 625
- ↑ Kolbe, p. 262
- ↑ Gooders and Boyer, p. 76
- ↑ Gooders and Boyer, p. 76
- ↑ Kolbe, p. 262
- ↑ Collin Harrison and Peter Castell: Field Guide Bird Nests, Eggs and Nestlings , HarperCollins Publisher, revised edition from 2002, ISBN 0007130392 , p. 74
- ↑ Collin Harrison and Peter Castell: Field Guide Bird Nests, Eggs and Nestlings , HarperCollins Publisher, revised edition from 2002, ISBN 0007130392 , p. 74
- ↑ Gooders and Boyer, p. 77
- ↑ Collin Harrison and Peter Castell: Field Guide Bird Nests, Eggs and Nestlings , HarperCollins Publisher, revised edition from 2002, ISBN 0007130392 , p. 74
- ↑ Bauer et al., P. 83
- ↑ Article in Birdlife international
- ^ Kolbe, p. 262 and p. 263
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 .
- Hartmut Kolbe; Die Entenvögel der Welt , Ulmer Verlag 1999, ISBN 3-8001-7442-1
- Erich Rutschke: The wild ducks of Europe - biology, ecology, behavior , Aula Verlag, Wiesbaden 1988, ISBN 3-89104-449-6
Web links
- Marmaronetta angustirostris in the endangered Red List species the IUCN 2008. Posted by: BirdLife International, 2008. Accessed January 31 of 2009.
- Videos, photos and sound recordings for Marmaronetta angustirostris in the Internet Bird Collection