Australasian Shoveler (Anas rhynchotis)

Australasian Shoveler

[order] ANSERIFORMES | [family] Anatidae | [latin] Anas rhynchotis | [authority] Latham, 1801 | [UK] Australasian Shoveler | [FR] Canard bride | [DE] Halbmond-Loffelente | [ES] Cuchara Australiano | [NL] Australische Slobeend

Subspecies

Monotypic species

Genus

Anas is a genus of dabbling ducks. It includes mallards, wigeons, teals, pintails and shovelers in a number of subgenera. Some authorities prefer to elevate the subgenera to genus rank.[1] Indeed, as the moa-nalos are very close to this clade and may have evolved later than some of these lineages, it is rather the absence of a thorough review than lack of necessity that this genus is rather over-lumped. The phylogeny of this genus is one of the most confounded ones of all living birds. Research is hampered by the fact the radiation of the two major groups of Anas ? the teals and mallard groups ? took place in a very short time and fairly recently, roughly in the mid-late Pleistocene. Furthermore, hybridization may have long played a major role in Anas evolution, with within-subgenus hybrids regularly and between-subgenus hybrids not infrequently being fully fertile.[1] The relationships between species are much obscured by this fact, and mtDNA sequence data is of dubious value in resolving their relationships; on the other hand, nuclear DNA sequences evolve too slowly to resolve the phylogeny of the subgenus Anas for example. Some major clades can be discerned. For example, that the traditional subgenus Anas, the mallard group, forms a monophyletic (in the loose sense, i.e. non-holophyletic) group has never been seriously questioned by modern science and is as good as confirmed (but see below). On the other hand, the phylogeny of the teals is very confusing. For these reasons, the dabbling duck lineages more distantly related to mallard group (which includes the type species of Anas) than the wigeons should arguably be separated in their own genera. These would include the Baikal Teal, the Garganey, the spotted black-capped Punanetta group, and the shovelers and other blue-winged species. Whether the wigeons, which are very distinct in morphology and behavior, but much less so in mtDNA cytochrome b and NADH dehydrogenase subunit 2 sequences, should also be considered a distinct genus Mareca (including the Gadwall and Falcated Duck) is essentially the one remaining point of dispute as regards the question which taxa should remain in this genus and which ones should not.

Physical charateristics

The Australasian Shoveler is a low-floating, dark headed duck, with a low sloping forehead blending to a heavy, square-cut, shovel-tipped bill. The male in breeding plumage has a deep grey-blue head with a vertical white crescent between the bright-yellow eye and the bill The back and rump are black, and the shoulder and wing coverts are blue-grey with several white bars. The underparts are chestnut, with white patches to the rear of the flanks. Outside the breeding season, the males are much duller. Females have mottled brown upperparts, chestnut underparts, and a dark brown eye. This species is also known as Spoonbill Duck, Shovelbill, Blue-winged Shoveler and Stinker.


wingspan min.: 70 cm wingspan max.: 80 cm
size min.: 46 cm size max.: 56 cm
incubation min.: 24 days incubation max.: 26 days
fledging min.: 55 days fledging max.: 70 days
broods: 1   eggs min.: 9  
      eggs max.: 11  

Range

Australasia : Australia, New Zealand

Habitat

The Australasian Shoveler is found in all kinds of wetlands, preferring large undisturbed heavily vegetated freshwater swamps. It is also found on open waters and occasionally along the coast.

Reproduction

The Australasian Shoveler breeds at almost any time in the arid parts of the continent, synchronised with flooding rains. Nests are built on the ground in dense vegetation, sometimes on a stump or hollow of a tree that is standing in water. The female alone incubates the eggs and broods the young. Clutch size is 9-11 eggs are laid; incubation period 25 days; young fledge after 8-10 weeks.

Feeding habits

The Australasian Shoveler is a filter feeder, using special lamellae (grooves) along the edges of the bill to filter insects, crustaceans and a variety of plants from the water. This specialised bill limits the Shoveler’s foraging range to aquatic habitats on open water or soft mud in fertile wetlands.

Video Australasian Shoveler

httpv://www.youtube.com/watch?v=ruYIkUY5N14

copyright: Stephen Wallace


Conservation

This species has a very large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be stable, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size may be moderately small to large, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
The Australasian shoveler was the first of the New Zealand ducks to take to the open ocean as a refuge from hunters. Their swift and erratic flight also aids in their survival but the species replies readily to decoys and callers. About 30,000 are shot each year in the duck shooting season, out of an estimated national population of just 150,000 birds. Unlike other dabbling ducks, the Australasian shoveler cannot supplement its diet by grazing on grass roots or grains. The edges of their bills have fine growths – lamellae – through which only soft foods can be sieved. They feed on fresh water invertebrates and the seeds of aquatic plants. They are sometimes found on flooded pasture but only to feed on worms and insects. The fertile, raupo-fringed lowland shallows that they prefer remain under constant threat of drainage.
Australasian Shoveler status Least Concern

Migration

In Australia these ducks are dispersive, but little is known about their movements. In New Zealand they are highly mobile.

Distribution map

Australasian Shoveler distribution range map

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