Efforts to reintroduce bilbies in the far south-west of New South Wales are showing signs of success, with numbers climbing to almost 2,000, seven years after the first breeding trial at Mallee Cliffs national park.
Fifty “founder” bilbies, including 30 from Thistle Island off the coast of South Australia, were released in a fenced breeding area in 2019 with the aim of establishing a wild population in the Mallee Cliffs habitat for the first time in a century.
Between 2021 and 2023, 107 bilbies were released from the breeding area into 9,570 hectares of fenced, predator-free habitat in the park. The Australian Wildlife Conservancy (AWC), which manages the conservation project with the state government, has conducted the first surveys and estimates the total population has now reached 1,840 bilbies.
Bilby emerges from burrow Credit: Australian Wildlife Conservancy
“Excluding bilbies from feral cat and fox impacts does really allow them to do well and breed up in numbers and persist in the environment,” said Rachel Ladd, an AWC wildlife ecologist.
She said the project team “definitely knew” a population boom was possible and it had been “wonderful” to see bilbies running around and turning soil over in the park.
Ladd said motion-sensor cameras showed the animals had dispersed through the wider fenced area and dug burrows to the point they were now occupying most of the predator-free habitat.
Scientist Rebecca West releases a bilby in the Wild Deserts precinct of Sturt national park. Photograph: Unsw Richard Freeman/Richard Freeman/UNSW
“We are picking them up on 95% of our cameras, which alone is a strong indicator that the population has spread across the safe haven and [is] utilising the full extent of the protected habitat,” she said.
The greater bilby is listed as vulnerable under Australia’s nature laws and is found in only about 20% of its former range in arid and semi-arid parts of the country.
The Mallee Cliffs project is one of six large predator-free areas with bilby populations managed by the AWC.
Ecologist releases a Bilby Credit: Australian Wildlife Conservancy
Across the properties in NSW, South Australia, Western Australia and the Northern Territory, the organisation’s annual bilby census found numbers had climbed from an estimated 3,300 in 2025 to 5,300 in 2026. The result is more than four times the population estimate in 2021 (1,230).
This includes an estimated 1,830 bilbies at Scotia Wildlife Sanctuary in south-west NSW, where the population has been steadily recovering after severe drought in 2018-19.
Ladd said the nature of arid areas made bilbies a boom and bust species, with the census results reflecting better environmental conditions for breeding. She said the population numbers were expected to fluctuate.
A bilby at Mount Gibson. Photograph: Zarah Wessels/Australian Wildlife Conservancy
“In good times, they are capable of breeding up and increasing their population size relatively rapidly and in dry times their population declines,” she said.
“Depending on how dry it gets there can be crash but they do persist and then build up their numbers again.”
At the Newhaven Wildlife Sanctuary on Ngalia Walpiri and Luritja country in the NT, the survey showed a rapid increase in numbers from 66 founder bilbies three-and-a-half years ago to an estimated 530, driven partly by above average rainfall. Ecologist Tim Henderson said the bilbies – which are known as ecosystem engineers – were reshaping the landscape at Newhaven as they foraged and burrowed.
“Their digging turns over large amounts of soil, helping retain rainfall and promote new vegetation growth,” he said.