Commonly Observed Native Animals in the NT
Magpie goose (Anseranas semipalmate)
Family: Anatidae
Other names: Black-and-white, Pied or Semi-palmated goose
Conservation Status
- Australia: Least Concern
- NT: Least Concern
Description
The Magpie goose is a large, distinctive waterbird that grows up to 90cm, slightly smaller than a Black swan. The adult Magpie goose has black and white feathers, a long neck and a cranial knob (smaller in females). They also have orange legs with partly webbed feet, and a red beak with a white hook on the end which assists them in probing for food.
Immature birds are like the adult but without a cranial knob; the black plumage is grey to brown.
The Magpie goose is well known for its call, a distinctive nasal “honk” noise.
Distribution
The distribution of the Magpie goose is dependant on the availability of surface water and, while it has been found in the temperate south-east of Australia, it has since disappeared. The main distribution is in the monsoonal wetlands from Derby, WA across the NT and Mackay, Qld. Magpie geese also occur in Papua New Guinea and Irian Jaya.
The NT holds the largest populations and breeding areas of the Magpie goose with an estimated population of over 2 million individuals.
Large flocks of Magpie geese can be seen close to wetlands and river systems.
Ecology
Magpie geese move in flocks over great distances especially in the wet season. Their diet is primarily herbivorous (plants) but young geese also consume invertebrates.
Magpie geese breed primarily late in the wet season in large breeding colonies. There is a population bias in mature geese for more females with each breeding male often having two females to breed with. Each female lays eggs, but where there are two females in one nest, less eggs are laid per female than if it is only a male-female pair. Incubation is shared by all parents.
Potential Threats
Major potential threats to Magpie goose populations include habitat removal and degradation to wetlands, climate change leading to saltwater intrusion, invasion of wetlands by introduced hooved animals and the increase of wetland weeds such as Mimosa pigra.
Another potential threat to the species is hunting, particularly if it is not managed to be sustainable. The Department of Natural Resources, Environment, the Arts and Sport (NRETAS) limit hunting to 3-4 months of the year, for which a permit is required; recreational hunting takes less than 2% of the population per year.
Lead shot toxicity is also a threat to Magpie geese, with lead shotgun pellets contributing to the accumulation of heavy metal in the water and in animals inhabiting those waters. Geese are known to ingest the pellets to use them for grinding up food. The threat of lead-toxicity will hopefully be decreased with non-toxic shotgun pellets being promoted throughout the NT.
Impacts
Magpie geese can become a pest to agricultural crops by eating seeds, fruits and young plants and damaging plants by trampling.
Conservation management and objectives
A management plan has been released for the Magpie goose in the NT for 2008-2013. This document details the actions and monitoring of Magpie geese populations that the Territory Government will take to secure the species in the NT.
Priorities of the current management plan are:
- To maintain viable populations of the Magpie goose
- To promote the long-term protection of the wetland habitats on which Magpie geese and other wetland fauna depend
- To facilitate, where appropriate the sustainable use of Magpie goose populations, and
- To provide ongoing refinement of Magpie goose management through timely evaluation of this management program.
Further Reading
Delaney R., Heywood M. and Fukuda Y. (2008). Management program for the Magpie goose (Anseranas semipalmata) in the Northern Territory of Australia, 2008 – 2013. Northern Territory Department of Natural Resources, Environment and the Arts, Darwin.
Marchant, S. and Higgins, P. (1990) Handbook of Australian, New Zealand and Antarctic Birds, Vol. 1- Ratites to Ducks, Oxford University Press, p1114-1123.
Simpson, K., Day, N. and Trusler, P. (1996) Field Guide to the Birds of Australia (5th ed.), Penguin Books, p52.
