Threatened Species of the Northern Territory

CARPENTARIAN GRASS-WRENAmytornis dorotheae

DescriptionThe Carpentarian grasswren is a medium sized grasswren with slender body and rusty-coloured back. The face is streaked black and white with a white throat in both males and females. The crown, nape and back are streaked by white feather shafts. The tail is rusty grey and held largely upright. Adult females differ from males by having the colour of the flanks, thighs and lower belly dark chestnut rather than tawny.

DistributionThis species is restricted to sandstone outcrops within the Carpentarian and Adelaidean Systems of the Gulf of Carpentaria. Sightings are infrequent and patchy within this distribution, but the species has occurred at Nathan River Station (NT) in the north to Westmoreland Station (Qld) in the southeast of the range (Garnett et al. 2011).

Conservation reserves where reported:Caranbirini Conservation Reserve.

EcologyLittle information is available on the ecology of this species. It is known to live amongst mature stands of spinifex (Triodia pungens) on sandstone outcrops containing large boulders. Grasswrens normally abandon burnt areas, unless substantial unburnt pockets of spinifex

Known locations of the Carpentarian grasswren

remain (Garnett et al., 2011). The birds nest within spinifex clumps during the wet season. Clutch size appears to be 2

For more information visit www.denr.nt.gov.au

Photo; Graeme Chapman

Conservation statusAustralia: EndangeredNorthern Territory: Endangered

– 3 eggs and young are fed on a variety of seeds and insects.

Habitat of the Carpentarian grasswren.

Conservation assessmentIn the Northern Territory, there have been two major surveys of the distribution of this species, by Martin and McKean (1986) in 1986 and Perry in 2005 (Perry 2005). Martin and McKean found that the species was patchily distributed in sandstone ranges in the southwest of the Gulf of Carpentaria hinterland. Perry (2005) re-sampled eight sites where the species had previously been reported and found grasswrens at only one of these sites, on Wollogorang Station. This small sub-population (across two locations) may be the only one persisting in the Northern Territory. The nearest other recent records are in the Lawn Hill area in Queensland (Garnett et al. 2011). Perry (2005) also reported that prevailing fire regimes across most of the sandstone environments in the region were unsuitable for this species.

The Carpentarian grasswren is considered Endangered (under criteria B1ab) due to:

extent of occurrence estimated to be <5000 km2;

severely fragmented population; and

continuing decline in range, habitat quality and population size.

Threatening processesFire is currently thought to be the primary factor influencing the distribution and abundance of the Carpentarian grasswren. Results from studies elsewehere (M. Lewis pers. comm.) indicate lowered seed availability from Triodia pungens after a history of annual dry season fires. The Carpentarian Grasswren not only uses unburnt patches of T. pungens as habitat but also feeds on the seeds of this species. Annual fires therefore reduce both food availability and habitat suitability. Fire caused the extirpation of the Borroloola subpopulation in the Northern Territory, has greatly reduced two other subpopulations and was probably responsible for the historical separation of the species into four specific subpopulations (Garnett et al., 2011). Conservation objectives and management

Research priorities are to: (i) monitor population numbers and

make a thorough investigation of the biology of the species.

Management priorities are to:(ii) improve current burning practises

by reducing the extent and incidence of late hot dry season burns, and introduce a balanced mosaic of burns.

Compiled bySimon WardJohn Woinarski[updated May 2016]]

ReferencesGarnett, S.T., Szabo, J.K. and Dutson, G. (2011).

The Action Plan for Australian Birds. 2011. (CSIRO Publishing/Birds Australia, Melbourne.)

McKean, J.L., and Martin, K.C. (1989). Distribution and status of the Carpentarian Grass-wren Amytornis dorotheae. NorthernTerritory Naturalist 11, 12-19.

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Perry, J. (2005). Habitat and status of the Carpentarian grasswren (Amytornis dorotheae) in the Northern Territory. B.App.Sci. thesis. (Charles Darwin University, Darwin.)

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