Australian Shelduck (Tadorna tadornoides)

Australian Shelduck

[order] ANSERIFORMES | [family] Anatidae | [latin] Tadorna tadornoides | [authority] Jardine and Selby, 1828 | [UK] Australian Shelduck | [FR] Tadorne d’Australie | [DE] Halsband-Kasarka | [ES] Tarro Australiano | [NL] Australische Bergeend

Subspecies

Genus Species subspecies Region Range
Tadorna tadornoides AU Australia

Genus

The shelducks, genus Tadorna, are a group of large birds in the Tadorninae subfamily of the Anatidae, the biological family that includes the ducks and most duck-like waterfowl such as the geese and swans. The namesake genus of the Tadorninae, Tadorna is very close to the Egyptian Goose and its extinct relatives from the Madagascar region, Alopochen. While the classical shelducks form a group that is obviously monophyletic, the interrelationships of these, the aberrant Common and especially Raja Shelducks, and the Egyptian Goose were found to be poorly resolved. Fossil bones from Dorkovo (Bulgaria) described as Balcanas pliocaenica may actually belong to this genus. They have even been proposed to be referable to the Common Shelduck, but their Early Pliocene age makes this rather unlikely.

Physical charateristics

Australian shelducks are 55-72 centimeters in length and weigh 1,020-2,040 grams.They are brightly coloured, large-bodied ducks with small heads and beaks. Males have black feathers tinged with green on the neck and head, with a white collar around the base of the neck. The breast and mantle are orange-brown or cinnamon and the rest of the underparts are blackish brown to black. Females have a white ring around the eye and the base of the beak and a chestnut-coloured breast. Immature birds are similar in appearance to females but have more white around the eye. Both males and females have a speculum (the upper surfaces of the wing feathers closest to the body) that is large and shiny-green with black at the margins.

Listen to the sound of Australian Shelduck

[audio:http://www.planetofbirds.com/MASTER/ANSERIFORMES/Anatidae/sounds/Australian Shelduck.mp3]

Copyright remark: Most sounds derived from xeno-canto


wingspan min.: 94 cm wingspan max.: 130 cm
size min.: 56 cm size max.: 72 cm
incubation min.: 30 days incubation max.: 33 days
fledging min.: 50 days fledging max.: 70 days
broods: 1   eggs min.: 8  
      eggs max.: 10  

Range

Australasia : Australia. In Western Australia, Australian shelducks have a large range south of the Tropic of Capricorn and east to Lake Carnegie, Laverton and Eucla.

Habitat

Shelducks are commonly found in estuaries and salty or brackish lakes but are also found on freshwaters (farm dams), sheltered seas and wet paddocks.

Reproduction

Shelducks usually breed on fresh waters and salt lakes which have been freshened with soaks or flood waters. The lakes may be inland or on islands like Rottnest and Carnac. Pairs vigorously defend their breeding territory which may cover a whole dam or a portion of a large water body. Pairs probably remain together for life.
Between May and October, 5-24 eggs are laid in a eucalypt or sandbank hollow and the female incubates the eggs for 30-32 days. Eggs may also occasionally be laid on the ground, in hollow stumps, in limestone caves or on island cliff ledges. The birds often return to the same nesting site year after year. During this time, the male defends a separate territory, where the young will be reared, which may be some distance from the nest site. When the ducklings are about two days old, they are led to this territory by their parents

Feeding habits

The Australian shelduck grazes on seeds, tubers, grasses, cereal and vegetable crops. It also consumes a variety of insects and molluscs. The birds search for food in short grass, as well as up-ending their bodies in shallow water. On Rottnest Island, brine shrimps are an important food.

Video Australian Shelduck

httpv://www.youtube.com/watch?v=7Oxrm5Oh7kw

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 increasing, 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 is very large, and hence does not 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 Australian shelduck is a declared pest of agriculture under the provisions of the Agriculture and Related Resources Protection Act 1976, administered by the Western Australian Department of Agriculture and Food. This declaration allows for the approval and implementation of a management program in various areas of the state. As a native species, the Australian shelduck is protected under the provisions of the Wildlife Conservation Act 1950, administered by the Department of Environment and Conservation (DEC). Under this Act shelducks can be shot on private land between the 1 January and the 30 June each year in accordance with a restricted open season notice, without the need to obtain a damage licence from DEC. The area covered by the notice comprises the south-west land division and Eucla division but excludes the Perth metropolitan region and the district of Mandurah. Shelduck populations in this area are secure and damage to agriculture is likely to be a continual problem.
Australian Shelduck status Least Concern

Migration

Mainly sedentary but local movement have bee nrecorded post-breeding.

Distribution map

Australian Shelduck distribution range map

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