The Tasmanian Native-hen (Gallinula mortierii) is a flightless water hen, one of twelve species of birds endemic to Tasmania. Many flightless birds have a sad history of extinction at the hands of man. The Tasmanian Native-hen has actually benefited from the introduction of european style agricultural practices in Tasmania (Ridpath: 1964).
| Tasmanian Native-hen | |
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| Species: | G. mortierii
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| Gallinula mortierii | |
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Tribonyx mortierii | |
Nomenclature
Other common names are Narkie, Native-hen and Waterhen. This species was originally descibed in 1840 as Tribonyx mortierii. The name mortierii is in honour of Bartholomé Charles J. Comte Dumortier (Marchant and Higgins: 1993)
Description
The Tasmanian Native-hen is a stocky flightless bird between 43 and 51 cm in length. The upperparts are olive brown with a white patch on the flank. The underparts are darker with a bluish grey tinge. The short tail is close to black and mostly held erect.The legs are thick and powerful, with a grey scaly appearance and sharp claws. The eye is bright red. Bill has a small frontal shield and is a greenish yellow (Watts:1999).
The juvenile bird is similar in appearance to the adult, but the colours are more subdued on the body and the underparts have fine white spots. The bill is dusky grey and the eyes are brown (Marchant and Higgins: 1993).
Chicks are covered in a dark brown fluffy down.
The species is easily identifiable, without easily confused species in Tasmania.
Habitat and distribution
The Tasmanian Native-hen is a sedentary species, living around open grassy areas close to water. It is widespread in Tasmania apart from the west and south west regions. It is not found on King or Flinders Islands in Bass Strait (Thomas: 1979), though Michael Sharland (1958) does record it as being on Flinders Island . A population introduced to Maria Island has established. It is generally common and easily seen around bodies of water that have grassy verges. Fossil records indicate that the Tasmanian Native-hen was found on the Australian mainland until around 4700 years ago. Suggested reasons for its extinction there have included the introduction of the dingo (Marchant and Higgins: 1993),or an extreme dry period (Ford: 1989).
Behaviour and Social organisation
The Tasmanian Native-hen's social organisation has been extensively studied by Michael Ridpath. Tasmanian Native-hens live in groups of between two and five, plus the young birds from the previous breeding season. The sedentary nature of the species mean that these groups hold sharply defined territories of up to five acres, and repel transgression into their territory vigorously with calls and displays.
Although flightless, it is capable of running quickly and has been recorded running at speeds up to 30 miles per hour (approx 48 kilometres per hour)(Sharland: 1958).
Breeding
The breeding season begins in the period from July to September, depending upon rainfall and the availability of food.Birds will usually breed once per year, however in good years, with high availability of food, two broods may be produced (Sharland: 1958, Ridpath: 1964). The nest is a rough , flattened grass mattress, among taller grasses and is usually built close to water, or on damp ground. The eggs measure approximately 56mm x 38mm and are a dull yellow to brown with some spotting of reddish brown and lavender (Beruldsen: 2003). As well as the primary nest, nursery nests are constructed with the purpose of roosting with chicks at night and as hiding places in case of predators (Ridpath: 1964).
Diet
The diet of the Tasmanian Native-hen is mostly made up of grass shoots and the leaves of low herbs which is grazes during daylight hours(Ridpath: 1964).The species has a reputation among farmers as an agricultural pest.The damage to agriculture was extensively studied in the 1960's by Michael Ridpath, who found that although there is some damage to crops, rabbits were generally a bigger pest to farmers.
Before european settlement in Tasmania, the cleared spaces required for feeding would probably have been provided by Indigenous burning of grasslands to provide feeding grounds for mammals, which would be hunted for food. The expansion of these cleared grassy areas has provided greater food sources and consequently greater numbers of the species within its range (Ridpath: 1964).
References
- Beruldsen, G. 2003. Australian Birds their nests and eggs. Kenmore Hills (QLD) G. Beruldsen.
- Ford, H.A.1989. Ecology of Birds: An Australian perspective. Chipping Norton: Surrey Beattie and Sons..
- IUCN 2006. 2006 IUCN Red List of Threatened Species. <www.iucnredlist.org>. Downloaded on 20 April 2007.
- Marchant, S. and Higgins, P.J.(Eds). 1993. Handbook of Australian and, New Zealand and Antarctic Birds. Volume 2: Raptors to Lapwings. Oxford University Press, Melbourne.
- Ridpath, M.G. and Meldrum G.K. 1968. Damage done to pastures by the Tasmanian Native hen, Tribonyx mortierii, in CSIRO Wildlife Research, 1968, 13, 11-24.
- Ridpath, M.G. 1964. The Tasmanian Native Hen.Hobart: CSIRO, Division of Wildlife Research.
- Sharland, M. 1958. Tasmanian Birds: a field guide to the birds inhabiting Tasmania and adjacent islands, including the sea birds. Sydney: Angus and Robertson.
- Thomas, D. 1979. Tasmanian Bird Atlas. Hobart: University of Tasmania.
- Watts, D. 1999. Field guide to Tasmania Birds. Sydney: New Holland.
External links
Tasmanian Parks and Wildlife service: Tasmanian Native-hen information
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