Crested duck
| Crested duck | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Crested ducks |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name of the genus | ||||||||||||
| Lophonetta | ||||||||||||
| Riley , 1914 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Lophonetta specularioides | ||||||||||||
| ( King , 1828) |
The crested duck ( Lophonetta specularioides ) is a South American duck bird that belongs to the swimming ducks. Today it is counted as the only species of the genus Lophonetta , as it split off from the other species of the Anatinae very early in its development . It used to belong to the genus of real ducks .
The crested duck is a medium-sized species of duck with an elongated body. Their tail appears long in relation to their body size, the bonnet is short but noticeable. The IUCN classifies the species as currently harmless ( least concern ).
Appearance
The crested duck is a medium-sized, gray-brown spotted duck. It reaches a body length of 50 to 60 centimeters. The weight varies between 900 grams and 1.1 kilograms. The species has no sexual dimorphism . The males are, however, much larger and more clearly drawn. The eponymous crest occurs in both sexes. In the females it is just a little shorter. In the natural range there is hardly any risk of confusion with other duck species. The steamship ducks of the distribution area all have a blue-gray plumage and are significantly more massive. The pointed-tailed duck have a significantly browner plumage and the copper mirror has a striking white spot on the face, which is missing in the crested duck.
The crested duck's neck, chin and face are pale gray. The feathers of the mantle, the back and the wing coverts are dark brown with lightened This gives the ducks the spotted appearance. The top of the head is dark brown. The area around the eyes is black. The wing mirror is metallic purple or bronze colored and has a wide white border. The eye is red to yellow. Beak, legs and feet are dark gray. Young birds are similar to adults. But they still lack the forelock and the black spot around the eye is less pronounced.
The top of the body of the chicks is light earth brown. The headstock, the eye stripe and the wings are colored a little darker. The rear wing hem and a large stain on the rump sides, the chest and the belly are dirty white. The bill and feet are gray.
voice
Crested ducks are very fiery ducks. They often let their calls be heard during the courtship season and when defending their breeding grounds. The females call during this time even when they are sitting on the nest. Most female ducks do not make any sounds from the nest so as not to attract the attention of predatory mammals and birds of prey.
The male gives a rough whorr and a humming sounding wheeoo . The female calls out a dark barking grruf and a nasal quek-quek-quek .
Distribution and existence
The nominate form is a resident bird and partial migrant in a distribution area that extends from Talea in Chile and Mendoza in Argentina to Tierra del Fuego . Partial migrants are in particular the crested ducks that settle in higher elevations. On the Falkland Islands , where the crested duck is one of the most common and widespread ducks, the nominate form is a resident bird. The population size of this subspecies is estimated at 10,000 to 25,000 individuals breeding pairs.
The subspecies L. s. alticola is a breeding bird of high Andean lakes in Peru and occurs in a southerly direction to the Junín region. It also lives in southern Bolivia, as well as in northern Chile and in the far west of Argentina. Crested ducks of this subspecies often breed at altitudes above 4,000 meters. In the so-called Punazone , the Andean crested duck is the most common duck bird. The population of this species is estimated at 100,000 individuals. In the winter months they move to altitudes of 2,000 meters above sea level. The range of both subspecies overlaps in the north of Chile.
Habitat and food
The crested duck inhabits marshes, moist pastureland and lakes. It occurs from the lowlands on the coast up to altitudes above 4,000 meters. The habitat used by it are depressions and river valleys in the foothills of the Andes, the Argentine pampas and the sub-Antarctic grass steppes in southern South America, as well as plateau lakes in the Andes. She prefers shallow waters and also accepts waters that have an exposed shoreline. Waters with floating leaf vegetation or extensive reed zones are avoided by it. It is also found in coastal bays and on beaches. They often examine the washed up kelp for food. In particular, the nominate form prefers plankton-rich brackish waters. On large lakes, swarms form outside of the breeding season. According to the ornithologist Hartmut Kolbe, crested ducks colonize even the smallest steppe ponds on the Strait of Magellan and Tierra del Fuego.
The crested duck feeds primarily on animals and mainly eats shellfish and crustaceans. Plant food is also consumed, but overall it does not play a major role.
Reproduction
The breeding time of the crested duck varies greatly depending on the geographical location of the occurrence. Since the duck broods two to three times a year, brooding crested ducks can be observed all year round. The main breeding season falls in the Andes in the months October to April. In southern South America, crested ducks breed mainly in the months of September to January.
Crested ducks have a large repertoire of courtship gestures, they are also very happy to call during this time. During the breeding season, they are very aggressive towards other species and also drive other bird species out of their breeding ground. Males and females often drive away territory invaders together. During this time they also drive away significantly larger water birds such as Magellan geese .
The nest is built on the ground and is usually located near the shore. The full clutch consists of five to eight eggs. These are cream colored and oval. The female breeds alone. The incubation period is 30 days. The male is involved in the rearing of the chicks. The chicks fledge after ten to eleven weeks.
Internal system
There are two subspecies. The nominate form Patagonian crested duck ( Lophonetta specularioides specularioides ) is common in southern Chile, Argentina and the Falkland Islands. The subspecies Andean crested duck ( Lophonetta specularioides alticola ) ( Menegaux , 1909) occurs in the mountainous regions of Peru, Bolivia, northern Chile and Argentina. The Andean crested duck is slightly larger, more brownish overall and has more uniformly colored plumage. The iris looks more yellow than in the nominate form.
Both subspecies are not threatened.
Keeping in human care
Crested ducks only rarely made it to Europe or North America until around 1950. The first holders are unknown. However, it is known that the London Zoo kept a single crested duck between 1887 and 1896. The Berlin Zoological Garden kept crested ducks around 1932. The first breeding in human care was achieved by the London zoo in 1948. The Andean crested duck was involved. The nominate form was first bred in Slimbridge in 1964 by the British Wildfowl Trust . Because of their great aggressiveness during the breeding season, they are usually kept in individual enclosures.
supporting documents
literature
- 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
- Hadoram Shirihai: A Complete Guide to Antarctic Wildlife - The Birds and Marine Mammals of the Antarctic Continent and Southern Ocean , Alula Press, Degerby 2002, ISBN 951-98947-0-5
- Robin and Anne Woods: Atlas of Breeding Birds of the Falkland Islands , Anthony Nelson, Shorpshire 1997, ISBN 0-904614-60-3
Web links
- BirdLife factsheet on the crested duck
- Lophonetta specularioides inthe IUCN 2013 Red List of Threatened Species . Listed by: BirdLife International, 2012. Retrieved October 11, 2013.
Individual evidence
- ↑ Johnson , Kevin P. & Sorenson , Michael D. (1999): Phylogeny and biogeography of dabbling ducks (genus Anas): a comparison of molecular and morphological evidence. Auk 116 (3): 792-805. PDF full text
- ↑ BirdLife Factsheet on the Crested Duck , accessed on November 26, 2010
- ^ Kear, p. 485
- ↑ Kolbe, p. 180
- ^ Kear, p. 485
- ^ Wood, p. 91
- ^ Kear, p. 485
- ↑ Kolbe, p. 181
- ^ Kear, p. 485
- ↑ Kolbe, p. 181
- ↑ Kolbe, p. 181
- ^ Kear, p. 486
- ^ Kear, p. 486
- ↑ Kear, p. 484
- ^ Shirihai, p. 249
- ↑ Kolbe, p. 182
- ↑ Kolbe, p. 182