The rather lovely Hardhead Aythya australis is the only true diving duck found in Australia, and will be immediately recognisable to birders familiar with eg the Ferruginous Duck as an aythya pochard. Common in the south-east of Australia, particularly in the Murray-Darling Basin, 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.
Hardheads (I’ve no idea where the name came from – one that’s totally useless in terms of helping identify the species – but maybe a typical 19th century Aussie night out used to involve getting drunk and head-butting ducks, and word soon spread that this was one mean aythya to avoid?) are also known as White-eyed Ducks for obvious reasons, and are found in freshwater swamps and wetlands and occasionally in sheltered estuaries. These ones were part of a loose flock of about twenty I saw on the main lake in Centennial Park in January 2009 (thinking about it they were not mingling with the very common Pacific Black Ducks – maybe they know as well what it’s like to get ‘nutted’ by a Hardhead).
(Range map copyright Birds Australia) According to BirdLife International this species has a large range, with an estimated global Extent of Occurrence of 100,000-1,000,000 km². It has a large global population estimated to be 100,000-1,000,000 individuals (Wetlands International 2002). Global population trends have not been quantified, but the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e. declining more than 30% in ten years or three generations). For these reasons, the species is evaluated as Least Concern.
However a cautionary note comes from http://wiserivers.nationalparks.nsw.gov.au, which says that “The regulation of water, altering flood patterns, is believed to have contributed to the decline of this duck, which is now rare along the southeast coast.”
|Male Hardheads. Only males have the gleaming white eye that gives the species its alternative name of White-eyed Duck. Both sexes though have chestnut upperparts, white bellies, white undertail coverts, and (in flight) white trailing wing edges and white underwings.|
|Female Hardhead. Note brown eyes and less rich plumage. Note also on the standing bird the typical leg and foot structure of a diving duck: the feet are large and powerful and the legs are set relatively far back, both adaptations which aid in diving and swimming underwater.|
Other references: http://bird.net.au.
All photos copyright Charlie Moores 2009