Australian shoveler
| Australian shoveler | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Australian shoveler ( Spatula rhynchotis ), here the subspecies New Zealand shoveler |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Spatula rhynchotis | ||||||||||||
| Latham , 1801 |
The Australian shoveler ( Spatula rhynchotis , Syn . : Anas rhynchotis ), also called the half-moon shoveler , is a species of the duck bird family . It occurs in two subspecies. The nominate form Spatula rhynchotis rhynchotis is part of the fauna of Australia , while the New Zealand shoveler is native to New Zealand.
The IUCN classifies the Australian shoveler as not endangered ( least concern ).
Appearance
Appearance of adult Australian shovelers
The Australian shoveler is a medium-sized, slender duck. It reaches a body length between 46 and 53 centimeters. It weighs an average of 665 grams. The wingspan is 70 to 80 centimeters. The species shows a conspicuous sexual dimorphism . In the magnificent dress the male has a blue-gray head. The head plumage shines weakly. What is striking is an elongated, white line that runs down from the front of the eye. It is particularly pronounced in the New Zealand subspecies. Its shape is variable, sometimes it is almost crescent-shaped. In the nominate form it is only hinted at. The parting and the throat are black-gray. The underside of the body is gray. the feathers of the breast have light-colored seams of different widths, so that the breast appears scaly. This is particularly noticeable in the New Zealand subspecies, where in some years the edges are wide white. In some years, however, the same individuals only have breast feathers lined with narrow, light cream-colored fringes.
The sides of the body are bright red-brown to chestnut brown. There is a noticeable white spot on each of the flanks. The back plumage is dark black-brown. The lower tail cover is colored a little lighter brown. When the Australian shoveler is resting or swimming, elongated feathers are noticed on the sides, some of which have white feather shafts. The bright green wing mirror, which is bordered by a wide white band, is noticeable in flight . The large, chunky beak is blackish-gray, the eyes are yellowish. Legs and feet are orange. In the resting plumage, the male of the nominate form resembles the female. However, the male is overall a little more reddish brown than the female. The eyes are yellowish even when they are resting. In the New Zealand subspecies, the dorsal feathers are black-green with narrow hems when the male is resting. The females of this subspecies have feathers on the back with broad dark brown borders.
The female has brown spotted plumage. Her eyes are brown, and legs and feet are a brownish orange. Her wing mirror is also noticeable in flight. However, it is browner overall.
Appearance of the chicks and fledglings
The chicks resemble those of the other shovelers, even if their downy dress is overall darker than that of other shovellings. The crown, the back of the neck and the top of the body are dark brown. The cheeks and the underside of the body are pale straw yellow. There is a yellow spot on each side of the body and the wings also have a yellow spot. A dark streak of eyes runs from the beak to the back of the head. The chicks of the Australian shoveler also have dark ear tags. The bill is mostly dark gray and the feet and legs are dark brown. Young birds are similar to females. The plumage on the chest and the lower neck is, however, slightly more striped.
_(1).jpg)
Possible confusion with other species
The Australian Shoveler is a typical Shoveler that their shape to the Eurasian spoonbill , African Kaplöffelente and the Argentine shoveler recalls. Like all of these ducks, it has a massive bill that tapers at the front. In its range, it cannot normally be confused with any other species of duck. However, the Eurasian shoveler occasionally comes to Australia as a random visitor . The Eurasian shoveler, however, has a bottle-green head with a white forehead and a white front chest. The rose-eared duck , also found in Australia, has a similarly large, chunky beak. However, this duck is much smaller, has a different body shape and a striking black and white head markings.
Distribution and existence
The Australian shoveler is a species of duck endemic to Australia and New Zealand. In Australia, their range is disjoint . One population lives in southwest Australia. The distribution area in the east of Australia is considerably larger. Here the main distribution area is in the south. They are particularly abundant in the Darling and Murray Rivers . In its eastern range, the Australian shoveler also reaches the tropical north of Australia. Also Tasmania is inhabited by the Australian Shoveler.
In New Zealand, the Australian shoveler is represented on both islands with a subspecies known as the New Zealand shoveler. The population of the New Zealand subspecies is estimated at 10,000 to 100,000 individuals. A similar range is given for the Australian subspecies. The total world population for both subspecies is between 100,000 and 300,000 individuals.
habitat
Australian shovelers live mainly in freshwater waters, where they strain the water with their beak in the shallow bank waters and on the mud banks. In recent years it has also increasingly colonized water retention basins in Australia. They prefer bodies of water whose water level fluctuates little seasonally and which are densely overgrown with aquatic plants. Australian shovelers rarely visit brackish waters, salt lakes and estuaries. In Australia, it penetrates further inland during periods of heavy rainfall. However, it only colonizes bodies of water that offer sufficient cover in the vicinity of the water body. Because of its dependence on rainfall, it occasionally occurs only on the lakes in the coastal area of Southeast Australia and on large watercourses with flood plains. During these times it can be observed in large swarms and is then also associated with Anas species.
Food and subsistence
The Australian shoveler feeds mainly on animals. The main components are water fleas , water insects and small mollusks . However, it also ingests seeds while foraging. Similar to the shoveler, it strains the water and presses the absorbed water out of its beak to the side. The food components remain in the beak blades. Rapid swimming can often be observed while foraging for food.
The Australian shoveler occasionally founds and even less often it dives for its food. It presumably sifts through the bottom sludge of water while diving.
Reproduction
Courtship
Australian shovelers have an extensive courtship repertoire. Usually several males courtship near the females. The courtship rituals include head shaking, head jumping up and rapid pumping movements with the head. This courtship movement, which both males and females show, also occurs in other shovelers. At the height of the courtship the males show a sham cleaning of the plumage as well as a ritualized wing flapping. Courtship males also follow the females in flight and such pursuit flights are an integral part of courtship. One of the most conspicuous courtship gestures is the male's flying up, in which it flies away from the female swimming in the water, but shortly afterwards drops back onto the water and flies back to the female and the courting group. These flights are often semicircular and are usually repeated several times by several males.
Raising the young
Australian shovelers nest individually. According to the current state of knowledge, they only raise one clutch per year. The nest is often well hidden in the vegetation some distance from the water. The nesting place is chosen by the pair of ducks. In Australia, oviposition usually begins in August. The breeding season of the New Zealand shoveler, on the other hand, falls from October to November. The eggs are elliptical to round-oval. The surface is smooth and shiny. The skin is light cream in color and has a slight bluish green tinge. A full clutch consists of nine to eleven eggs. The female breeds alone. The male leaves the female with the start of breeding and the onset of moulting. The incubation period is 24 to 25 days. The chicks, which are only led by the female, fledge after about eight weeks.
Attitude in Europe
The Australian shoveler is one of the species that was imported into Europe and North America relatively late. In 1934 one male and two females of the New Zealand subspecies were kept in France. The first breeding took place there in 1935. The British Wildfowl Trust , which succeeded in first breeding a number of duck species in the world and in Europe, kept Australian shovelers of the New Zealand subspecies again from 1960 and the nominate form from 1967. Both subspecies were successfully bred by the Wildfowl Trust. Since the beginning of the 1990s, however, the New Zealand shoveler has predominantly been kept in Europe. The Australian shoveler has almost completely disappeared from European husbandry due to inbreeding depression . The New Zealand shoveler also has the advantage of being a little more resistant to the cold than the Australian subspecies.
supporting documents
literature
- PJ Higgins (Ed.): Handbook of Australian, New Zealand & Antarctic Birds. Volume 1: Ratites to Ducks. Oxford University Press, Oxford 1990, ISBN 0195530683 .
- Janet Kear (Ed.): Ducks, Geese and Swans. Oxford University Press, 2005, ISBN 0198546459 .
- Hartmut Kolbe; The duck birds in the world. Ulmer Verlag 1999, ISBN 3-8001-7442-1 .
Individual evidence
- ↑ a b c Kear, p. 558.
- ^ Higgins, p. 1340.
- ↑ Kolbe, p. 229.
- ↑ Kolbe, p. 228.
- ↑ a b Kear, p. 559.
- ↑ a b c Kolbe, p. 230.
- ^ Higgins, p. 1341.
- ↑ a b Kear, p. 560.
Web links
- Spatula rhynchotis inthe IUCN 2013 Red List of Threatened Species . Listed by: BirdLife International, 2012. Retrieved February 6, 2014.