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Nov 15 2011

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Hardhead (Aythya australis)

Hardhead

[order] ANSERIFORMES | [family] Anatidae | [latin] Aythya australis | [authority] Eyton, 1838 | [UK] Hardhead | [FR] Fuligule austral | [DE] Tasman-Moorente | [ES] Porron Australiano | [NL] Australische Witoogeend

Subspecies

Monotypic species

Genus

Aythya is a genus of diving ducks. It has twelve described species. Aythya shihuibas was described from the Late Miocene of China. An undescribed prehistoric species is known only from Early Pleistocene fossil remains found at Dursunlu, Turkey; it might however be referrable to a paleosubspecies of an extant species considering its age. The Miocene “Aythya” arvernensis is now placed in Mionetta, while “Aythya” chauvirae seems to contain the remains of 2 species, at least one of which does not seem to be a diving duck.

Physical charateristics

Hardheads are small by duck standards, usually not much more than 45 cm long but reaching 60 cm sometimes, and noticeably more rounded in overall form than most ducks. Both male and female are a fairly uniform chocolate-brown above, with rufous flanks and white undersides (which are often not visible if the duck is in the water). The trailing edges and almost the entire underside of the wings are white. In the male, the eyes are a striking white, in the female, brown


wingspan min.: 65 cm wingspan max.: 70 cm
size min.: 46 cm size max.: 49 cm
incubation min.: 25 days incubation max.: 30 days
fledging min.: 0 days fledging max.: 0 days
broods: 1   eggs min.: 9  
      eggs max.: 13  

Range

Australasia : Australia. It is normally restricted to the coastal strip from the Fitzroy River, Western Australia, to Rockhampton, Queensland.

Habitat

Hardheads prefer larger lakes, swamps and rivers with deep, still water, but are often seen in smaller streams, flooded grasslands, and shallow pools. As a general rule, they avoid coastal waters. They rarely come to land and never perch in trees.

Reproduction

Hardheads breed in low, thick vegetation, in or near the water, along rivers and channels and around billabongs and dams. The nest is a trampled platform of reeds, sticks and vegetation, with some down lining. The nest is built by the female, and is often added to with what she can reach from the nest. She incubates the 9-13 eggs alone for about a month.

Feeding habits

Like the other members of the pochard group, Hardheads feed by diving deeply, often staying submerged for as long as a minute at a time. They slip under the water with barely a ripple, simply lowering their heads and thrusting with their powerful webbed feet. They eat a broad range of small aquatic creatures, and supplement this with water weeds. Mainly vegetarian: seeds, flowers, green parts grasses, sedges, aquatic plants; also (up to 10% of diet) aquatic invertebrates (insects and their larvae, mussels, crustaceans) and small fish

Video Hardhead

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

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 fluctuating, 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.
Hardheads have declined in some areas after draining of freshwater wetlands or diversion of water for irrigation
Hardhead status Least Concern

Migration

They are moderately nomadic in normal years, but disperse widely in times of drought. Significant numbers reach as far afield as New Guinea, New Zealand, and the islands of the Pacific, where they can remain for some time, even breeding for a season or two.

Distribution map

Hardhead distribution range map

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Permanent link to this article: http://www.planetofbirds.com/anseriformes-anatidae-hardhead-aythya-australis

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