It is a small songbird, with a distinctive squeaky song, that once ranged from Shark Bay in Western Australia to the Eyre Peninsula in South Australia. The species’ range declined dramatically after European colonisation due to habitat loss and is now restricted to Shark Bay and north-eastern Eyre Peninsula.
The translocation was informed by researcher Aline Gibson Vega’s PhD project and is part of a collaboration between DBCA, Bush Heritage Australia and the University of Western Australia.
Ms Gibson Vega determined from their genetics and behaviour that the best translocation approach for Dirk Hartog Island would be to mix birds from the subpopulations at Hamelin and Francois Peron. During mid-October, 85 birds from these two extant populations were translocated to maximise genetic diversity.
“It was so rewarding to see my research being used to inform the translocation planning and execution,” said Ms Gibson Vega. “If my modelling is accurate, the 85 individuals will create a selfsustaining population and we may not need to do any further 'top-ups' of individuals in future years - though long-term monitoring will confirm this.”
Conservationists from Bush Heritage and scientists from DBCA, along with a dedicated group of volunteers, captured family groups of grasswrens in specifically designed mist-nets and transported them to Dirk Hartog Island in a helicopter.
“It was very exciting to see the first grasswrens taking off to their new island home (now free of introduced predators) after all the research, planning, and hard work leading up to the moment,” said Dr Michelle Hall, Bush Heritage ecologist.
Some birds were fitted with transmitters to monitor their movements and survival after they were released onto the island.
DBCA scientist Dr Leanne van der Weyde said: “It was exciting to be a part of establishing a new population of grasswrens on the island as part of this world class project to conserve our native species and restore the fauna of the island.”
It is estimated that the habitat on Dirk Hartog Island will support up to 8000 pairs of western grasswrens and audio recording units will be used to monitor the birds in the longer term by recording their calls.
The Dirk Hartog Island Return to 1616 Ecological Restoration Project is funded by the GorgonBarrow Island Net Conservation Benefits Fund. Ms Gibson Vega’s research was supported by Bush Heritage’s Paul Hackett Memorial Scholarship and in-kind contributions from Return to 1616.
For more information, see the Dirk Hartog Island National Park Return to 1616 Ecological Restoration Project website.