Estuaries and their surrounding habitat provide an important food source for waterbirds.
For example, herons, bitterns and egrets feed on insects and small animals in saltmarshes, and wading birds like the bush stone-curlew, double-banded plover, bar-tailed godwit and sandpipers also forage in the shallow waters in saltmarshes.
Wading birds, such as the eastern curlew feed on fish, shrimps and other invertebrates in seagrass beds.
Freshwater vegetation in the upstream reaches of estuaries provides food for common waterbirds such as ducks, geese, black swans and common sandpipers.
Wading birds, such as the whimbrel and greenshank, feed on fish, crustaceans and other invertebrates in the shallow waters around mangroves.
The little penguin, which lives along the NSW coast south of Port Stephens, is often seen around the Hawkesbury region and Sydney. Breeding colonies are found on Lion Island near Pittwater and Montague Island near Narooma as well as on the mainland at Manly. Little penguins feed over a relatively large range from their nests, and often enter estuaries to catch squid and small fish.