Family ANSERANATIDAE Sclater, 1880
Introduction
Anseranatidae (Magpie Goose) have been separated as a distinct family unit by several authorities, e.g. Livezey (1986, 1997) and Christidis and Boles (2008). These distinctions and separations are based on DNA analysis and osteology characters while other authors have complimented the studies through their own investigations although they failed to realise the significance of their own work, e.g. Frith (1977). The family position suggests that the monotypic species is from an ancient lineage. Restricted to the one extant species, endemic to Australia and southern New Guinea, it has no subspecies.
Evidence suggests that the species once occurred across the Australian continent where it frequented wetlands in large gregarious flocks. During the 19th century the populations retracted to northern Australia but it appears to be once again establishing itself in southern areas. During the northern dry season, flocks gather at dwindling wetlands, moving out to expanding areas of swamp and lagoons during the onslaught of the wet season. Their vocalisations consist of series of loud gooselike honks used to communicate between pairs. They are principally herbivorous, also taking small marine invertebrates.
As the specific name suggests the toes of this bird are semipalmate, a character differing greatly from the webbed toes of the Anatidae. Breeding occurs in groups using wetland reedbeds at the onset of the wet season or abnormal rains; they are known to be attracted to crops such as rice fields where their nesting has been known to cause extensive damage. Like members of the Anatidae, pairs are maintained as succinct pairings and females construct the nest of reeds in extensive reedbeds. Incubation is undertaken by both sexes. The eggs, numbering up to 12 per clutch, have an elliptical shape with a slightly oiled appearance; the base colour is creamy white to white and is generally unmarked apart from staining through sitting on decaying nesting materials. The young are precocial and able to leave the nest shortly after hatching. They are attended to by the adult for the first few weeks after hatching but quickly become independent.
General References
Christidis, L. & Boles, W.E. 2008. Systematics and Taxonomy of Australian Birds. Melbourne : CSIRO Publishing 288 pp. [61]
Frith, H.J. 1977. Waterfowl in Australia. Sydney : A.H. & A.W. Reed 1st Edn, 328 pp.
Livezey, B.C. 1986. A phylogenetic analysis of recent anseriform genera using morphological characters. Auk 103(4): 737–754
Livezey, B.C. 1997. A phylogenetic analysis of basal Anseriformes, the fossil Presbyornis, and the interordinal relationships of waterfowl. Zoological Journal of the Linnean Society 121: 361–428