Dispersive, Irruptive, White-Eyed Diving Ducks… HardheadsA mild day in early spring is a great time for a wander through Centennial Park, even on a weekend when it can be busy. For peace and quiet you can stretch your legs away from the roads and tracks, taking advantage of the strengthening sun across open grassy spaces, or you can experience a fresh breeze under the shadow of shady trees in damp areas of low lying ground close to some of the quieter lake edges, or on higher, drier ground towards Oxford Street and York Road.
If you prefer company you might want to mingle with the people near the kiosk close to the Duck Pond; families with young kids enjoy feeding the ducks there. They can park close by and don’t have to walk too far.
In the water, swans, grebes, moorhens and coots compete with the ducks for food items offered by park visitors, while a few white ibises and seagulls hang around on land waiting for their chance to steal any misdirected snacks. Pacific Black Ducks and Grey Teal are the most obvious ducks but Chestnut Teal, Australian Wood Ducks and Hardheads are usually present too.
Hardheads are easy to identify among all the water birds as they have large, dark, high-crowned heads and appear more compact and streamlined in shape than other ducks. They are deep chocolate brown in colour with obvious square white patches under their tails. Drakes are immaculate with conspicuous white eyes, and their black bills are crossed with a prominent pale blue-grey band towards the black tip. Adult females are similar but paler in colour with dark eyes and blue-grey bills, while immature birds resemble females. Fast flying Hardheads show white bellies and underwings with striking, broad white bars along the rear upper surface of their wings – diagnostic for identification.
Hardheads prefer well-vegetated, deep freshwater habitats including large open waters, swamps, sewage ponds, dams, ornamental lakes and brackish coastal wetlands. They occur widely in Australia and Tasmania in suitable habitat but breeding is concentrated in the east, southeast and southwest of the mainland. After good rains, and following breeding, birds disperse to northern Australia, Tasmania and far inland, avoiding western deserts. They are predominantly opportunistic, irruptive and dispersive nomads that respond to flooding and drought, and also occur as irregular visitors in Indonesia, PNG, Pacific Islands and New Zealand. In Sydney numbers fluctuate depending on water conditions inland but generally they are moderately common residents.
A mixture of aquatic plants and animals is the preferred food for Hardheads, particularly mussels and freshwater shellfish. Most food is obtained by diving but birds also sieve waterside mud, upend like dabbling ducks, and strip seeds from growing plants.
Since European settlement there have been fluctuating changes in numbers and distribution of Hardheads in Australia, largely as a result of seasonal conditions, changes in water management and legal shooting pressure. Nevertheless, despite significant regional variation over the last 30 years or so, there have been no differences in overall numbers reported nationally and the future for Hardheads appears to be secure.