Aquatic, Unobtrusive, Widespread… Australasian Grebes

By Keith Hutton on December 15, 2010 in Other

Photo: David Webb

Grebes are strictly waterbirds that superficially resemble small unobtrusive ducks, except that they have pointed bills and no distinct tails, and their feet are positioned so far back that they are almost incapable of walking on land. Furthermore there are no intact webs between their long toes, which have an unusual arrangement of flattened lobes along them to assist swimming.

Grebes are almost completely aquatic, seldom seen flying, almost never ashore and superbly adapted to a submarine existence. They have no close relatives in the bird world but DNA studies suggest they have evolved from the same ancestors as penguins and pelicans. When threatened they patter across the water instead of flying, or they dive under the surface. They fly rapidly and cover great distances, but normally only at night. They occur on transient waters far inland after flooding and two Australian species have even reached New Zealand, where both have bred successfully, and where Australasian Grebes are now established residents.

All grebes have distinct breeding plumages and precocial, striped young. Their nests are floating damp platforms of waterweeds, usually anchored in shallow water, and when sitting birds leave the nest they cover their eggs before slipping off into the water. When the downy chicks hatch they can swim as soon as they are dry, but despite this they are often carried on their parents’ backs, even when the parents dive underwater to avoid predators.

The most familiar and widespread grebes in the Eastern Suburbs are Australasian Grebes. They are the smallest of the grebes that breed in Australia and are normally seen in pairs or family groups. If disturbed, they usually dive to flee the potential danger rather than fly away. In spring and summer they have a black head and neck with a chestnut stripe from behind the eye to the side of the neck, and a very obvious pale patch of yellow bare skin on the face, and yellow eyes. They are much smaller than ducks and have pale-tipped, dark pointed beaks. They are noisy in the breeding season and have far-carrying, chittering territorial calls.

Australasian Grebes prefer still, shallow, weedy, freshwater wetlands and are widespread and common in the east and southwest of Australia, irregular inland and less common in Tasmania and the north. In the Sydney region they are common on swamps and lagoons throughout; Centennial Park is a good place to look for them, particularly on Musgrave and One More Shot Ponds. They feed on the surface and underwater on small aquatic animals such as snails, fish, insects and their larvae, and crustaceans, and they can often be seen diving repeatedly for food.

The status of Australasian Grebes nationally is stable, although distribution may be modified by flooding and drought, and by the provision of farm dams and artificial ponds and lakes. Fluctuating water levels, weather and predation probably result in high losses but overall Australasian Grebes are prolific, mobile, opportunistic, and successful.