Breeding territories include freshwater swamps, brackish swamps, and inland lakes. They utilize grasslands, open woodlands, pastures, and agricultural fields for feeding. Post breeding birds form large flocks of thousands of birds in prime feeding or moulting habitat. Australian Shelducks are primarily grazing birds. They feed on short grasses and forbs in pasturelands.
Shelducks also dabble in shallow waters in search of aquatic invertebrates and submerged vegetation.
Hollow trees are the preferred nesting site. Where suitable tree cavities are scarce, shelducks will nest in rock crevices, shallow caves, holes in banks, or rabbit burrows. The newly hatched young leap from the nest cavity and are led by their parents on a perilous overland journey to their brooding territory. They remain together in a family group for the first six weeks of the ducklings' lives. Once the young birds fledge they are completely independent.