Bilby Reintroduction Effort in New South Wales Shows Population Growth

In 2019, 50 founder bilbies, including 30 from Thistle Island off South Australia, were released into a fenced breeding area at Mallee Cliffs National Park in far south-west New South Wales. The project aimed to reestablish a wild bilby population in the area for the first time in a century.

Between 2021 and 2023, 107 bilbies were moved from the breeding area to a larger 9,570-hectare predator-free zone in the park.

The Australian Wildlife Conservancy, working with the state government, conducted surveys that estimated the bilby population at Mallee Cliffs has reached 1,840 individuals. Rachel Ladd, a wildlife ecologist with the Conservancy, stated that excluding impacts from feral cats and foxes allows bilbies to thrive and increase in numbers.

Motion-sensor cameras detected bilbies on 95% of devices, indicating they have spread across and utilized the protected habitat.

The greater bilby is classified as vulnerable under Australian environmental laws and now occupies only about 20% of its historical range in arid and semi-arid regions. The Mallee Cliffs initiative is one of six large predator-free areas managed by the Australian Wildlife Conservancy that support bilby populations.

These efforts span New South Wales, South Australia, Western Australia, and the Northern Territory.

Across the Conservancy's properties, annual bilby censuses showed an increase from an estimated 3,300 individuals in 2025 to 5,300 in 2026, more than quadrupling from 1,230 in 2021. At Scotia Wildlife Sanctuary in south-west New South Wales, the population is estimated at 1,830 bilbies, recovering from a severe drought in 2018-19.

At Newhaven Wildlife Sanctuary in the Northern Territory, the population grew from 66 founder bilbies three-and-a-half years ago to about 530, partly due to above-average rainfall.

Bilbies act as ecosystem engineers by digging burrows and turning over soil, which helps retain water and promote vegetation growth. Rachel Ladd noted that bilbies are a boom-and-bust species in arid environments, with populations rising during favorable conditions and declining during dry periods.

Tim Henderson, an ecologist, observed that at Newhaven, bilbies are reshaping the landscape through their foraging and burrowing activities.

The surveys highlight how predator-free zones can support bilby recovery, but populations may fluctuate with environmental changes. The Australian Wildlife Conservancy plans to continue monitoring and managing these areas to sustain growth. Ongoing efforts aim to address threats like habitat loss and invasive species for long-term conservation.