In a major milestone, 85 Western Grasswrens have been successfully translocated to Dirk Hartog Island National Park in Western Australia to re-establish the population since it went locally extinct.
Some of the birds came from Bush Heritage Australia’s Hamelin Station Reserve on Malgana and Nanda Country, bordering the Shark Bay World Heritage Area, while others made the journey from nearby Francois Peron National Park.
The translocation is the first of its kind for grasswren species and is part of the Dirk Hartog Island National Park Return to 1616 Ecological Restoration Project, a major conservation science project run by the Department of Biodiversity, Conservation and Attractions (DBCA).
The project is using a science-based approach to return the vegetation and habitats of the island to the condition it was found in when first visited by the explorer Dirk Hartog in 1616.
The Western Grasswren is one of 13 species that did not survive the changes to the island’s ecology, brought on by the introduction of sheep, goats and feral cats.
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.
About Bush Heritage
Bush Heritage Australia is a leading not-for-profit conservation organisation that protects ecosystems and wildlife across the continent. We use the best science, conservation and right-way knowledge to deliver landscape-scale impact. We’re on the ground, working with Aboriginal and Torres Strait Islander people and the agricultural sector to make sure our impact is deep, sustainable and collaborative.
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