The Magpie-goose, Anseranas semipalmata, is a waterbird species found in coastal northern Australia and savannah in southern New Guinea. It is a unique member of the order Anseriformes, and arranged in a family and genus distinct from all other living waterfowl. The Magpie-goose is a resident breeder in northern Australia and in southern New Guinea.
Description
Magpie-geese are unmistakable birds with their black and white plumage and yellowish legs. The feet are only partially webbed, although the Magpie-goose will feed on vegetable matter in the water as well as on land. Males are larger than females. Unlike true geese, the moult is gradual, and there is no flightless period. The voice is a loud honking.
Systematics and evolution
This species is placed in the order Anseriformes, having the characteristic bill structure, but is considered to be distinct from the other species in this taxon. The related and extant families, Anhimidae (screamers) and Anatidae (ducks, geese and swans), contain all the other taxa. The Magpie-goose is contained in the genus Anseranas and family Anseranatidae, which are monotypic in our age.
This family is quite old, having apparently diverged before the Cretaceous"?Paleogene mass extinction - the relative Vegavis iaai lived some 68-67 million years ago. The fossil record is limited, nonetheless. The enigmatic genus Anatalavis (Hornerstown Late Cretaceous or Early Paleocene of New Jersey, USA - London Clay Early Eocene of Walton-on-the-Naze, England) is sometimes considered to be the earliest known anseranatid. Other Paleogene birds sometimes considered magpie-geese are the genera Geranopsis from the Hordwell Formation Late Eocene to the Early Oligocene of England and Anserpica from the Late Oligocene of Billy-Créchy (France). The Australian distribution of the living species ties in well with the presumed Gondwanan origin of Anseriformes, but Northern Hemisphere fossils are puzzling. Perhaps the magpie-geese were one of the dominant groups of Paleogene waterfowl, only to become largely extinct later.
Roosting
Ecology and status
The Magpie-goose is found in a variety of open wetland areas such as floodplains and swamps. It is fairly sedentary apart from some movement during the dry season. They are colonial breeders and are gregarious outside of the breeding season when they can form large and noisy flocks of up to a few thousand individuals. Its nest is on the ground, and a typical clutch is 5-14 eggs. Some males mate with two females, all of which raise the young, unlike some other polygamous birds. This may be beneficial when predation of young is high as chicks raised by trios are more likely to survive.
This species is plentiful across its range. For Australia as a whole, it is not threatened and has a controlled hunting season when numbers are large. However, most of the southern populations were extirpated in the mid-20th century by overhunting and habitat destruction. The species has been subject to reintroduction projects, and populations have again reached a level where it can be regularly utilized by hunters. In Victoria, the Magpie Goose was listed as near threatened on the 2007 advisory list of threatened vertebrate fauna in Victoria. In the December 2007 Flora and Fauna Guarantee Act list of threatened fauna, it is also listed. As of early 2008, an Action Statement for the recovery and future management of this species had not been prepared.
