Elusive species found on Stone Country
An elusive and threatened bird has been detected by the Territory NRM threatened species team and Indigenous rangers while conducting surveys in Arnhem Land.
Territory NRM have been working with the Warddeken Bininj and Daluk Rangers to look for the yirlinkirrkkirr (white-throated grasswren), a threatened species known from the Arnhem Land Escarpment, found in the sandstone heath shrubland.
The white-throated grasswren (Amytornis woodwardi) is listed as Vulnerable nationally, with frequent and intense fire and predation by feral cats major threats to it survival.
TNRM threatened species team leader, Dr Kelly Dixon, said the species was somewhat unusual for a bird in that it doesn’t fly often or far, and instead runs and hops across rocky outcrops.
“Their limited ability to travel very far makes them more susceptible to fire and predation, and when there are fewer patches of long-unburnt habitat for them to move between, they are unable to disperse she said.
TNRM is funded through the National Landcare Program to deliver a three-year project, aimed at improving or stabilising the trajectory of the species.
“They inhabit long-unburnt sandstone heath, and their preferred habitat has bare rocky outcrops for cover, old spinifex clumps for nesting in, and good shrub cover for feeding and cover,” Dr Dixon said. “This is very difficult country to access, which makes observing the species even more challenging.”
To overcome the challenge of requiring direct observation to obtain records of the species, TNRM supported the Warddeken Rangers to deploy motion sensor cameras and bioacoustics recorders (‘songmeters’), an emerging technology, across nine sites in April this year. Last week, the TNRM threatened species team travelled to Warddeken to assist the rangers in retrieving the equipment and to undertake call playback surveys.
“We conducted call playback surveys at thirty plots in five sites at the time of equipment retrieval, and five white-throated grasswrens were detected at one of the sites,” Dr Dixon said. “The species has been detected at this site in the past year by Warddeken during their extensive Mayh (animal) monitoring program using motion sensor cameras, so it was encouraging to know the grasswrens are persisting in this area. The camera trapping and songmeter data recently retrieved from Warddeken are yet to be analysed, but we hope to detect them at other sites in the IPA. One of the key outcomes of the white-throated grasswren project is to improve our knowledge of the species distribution across the Stone Country.”
The Warddeken Indigenous Protected Area (IPA) is a special place for the white-throated grasswren, as it has declined in many places at which it was formerly regularly sighted. Already, the results of predictive habitat modelling completed at the beginning of the project are informing the burning program in the Warddeken IPA to protect long-unburnt patches of the Stone Country. The recent surveys in Warddeken follow on from surveys TNRM completed with the Jawoyn Rangers in August last year on Jawoyn Country in the Manyallaluk Aboriginal Land Trust.
Further surveys are planned over the next 12 months in other areas of the Stone Country with various Ranger groups and results from these will continue to help inform fire management planning. All surveys are carried out under appropriate animal ethics, Northern Territory Government and Northern Land council permits.