Hardhead, Aythya australis
The Hardhead (aythya australis), also known as the White-eyed Duck is the only true diving duck found in Australia. Hardheads are familiar in the south-east of Australia, especially in the Murray-Darling Basin, but also in the wetter country near the coasts. They are somewhat drifting 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. Like the other members of the pochard group, Hardheads feed by diving deeply, usually staying submerged for as long as a whole minute at a time. They slip under the water with barely a ripple, lowering their heads and thrusting with their powerful webbed feet.
They eat a broad range of small aquatic creatures, and supplement this using water weeds. They prefer larger lakes, swamps and rivers with deep, still water, but are more often seen in smaller streams, flooded grasslands, and shallow pools. As a general rule, they avoid coastal water. They barely ever come to land and they never perch in trees.
They 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 sexes are a fairly uniform chocolate-brown above, with brownish-red 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. The eyes are striking white in the males but in the females they are brown.
Being widespread throughout its large range, the Hardhead is evaluated as Least Concern by the IUCN Red List of Threatened Species.
Image Caption: Hardhead (Aythya australis) male, Lake Dulverton, Oatlands, Tasmania, Australia. Credit: JJ Harrison/Wikipedia (CC BY-SA 3.0)