Lives in small parties to large flocks; keeps to water, sometimes on logs in the water or along the edges, but rarely on land. Roosts along the edge of water.
The flaps of skin along the bill form a broad scoop which the bird uses to scoop up food. They cruise the water with the bill immersed, sometimes up to the eyes; water is drawn in through the slightly opened tip of the bill, then pumped out the sides through fine lamellae or plates which filter the water and catch food particles.
Pink-eared Ducks often feed in arrowhead formation or several birds rotate clockwise or anti-clockwise; this is thought to be to stir up the bottom mud. They also trawl along the bottom. They eat insects, water fleas, freshwater algae and floating seeds.
This specialised feeding technique works best in plankton-rich, shallow, stagnant, fresh water so big flocks of Pink-eared Ducks congregate on floodsheets and claypans for the best feeding conditions.
Of necessity these birds are nomadic, always on the move looking for suitable bodies of water which are often temporary. Core breeding area is the Murray-Darling system
They rarely gather on deep lagoons and swamps where the feeding is not as good, except during drought when they resort to lakes and swamps when their preferred habitats have dried up. The Atherton photograph above was taken on a lake at Hasties Swamp near Atherton in Queensland in mid-2013 after a poor Wet Season when inland Queensland was entering a drought.
Breeding takes place at any time of the year when floodwaters are high enough. The nest is a rounded mound of sticky grey down 25 centimetres across and 15 centimetres high placed on a log, a limb or in bushes a few centimetres to 10 metres above the water; often old nests of other water birds are used. Five to eight eggs, usually six or seven, are laid; smooth, white or cream; oval, pointed at the smaller end, about 49 by 36 millimetres. The female incubates the eggs for about 28 days; the male remains throughout the incubation period defending the nest, then helps to raise the young. New pairs form at each breeding.