Mission to diversify endangered wallaby population in south-west NSW

Ecologists with Australian Wildlife Conservancy (AWC) travelled interstate on a delicate mission to fly the once believed-to-be extinct Bridled Nailtail Wallaby from eastern central Queensland to south west NSW. The translocation was part of a species management plan to improve the genetic diversity of the reintroduced population at Scotia Wildlife Sanctuary (Barkandji country).

Under the cover of night, a dozen ecologists, rangers from Queensland Parks and Wildlife Service (QPWS) and vets from Village Roadshow Theme Parks, used cage traps to catch 20 wallabies from QPWS’s Taunton National Park, located inland from Rockhampton. Taunton is home to the only remaining remnant population of the Bridled Nailtail Wallaby which was presumed extinct for three decades until an opportunistic sighting occurred at Taunton in 1973.

Luke Playford/AWC

Twelve males and eight females were successfully lured into lucerne baited traps. Each wallaby received a health check, clearing them for travel before they were carefully placed inside pet carriers for their three and a half-hour flight south. The bias towards male wallabies was intended to achieve the desired genetic supplementation at Scotia while minimising impacts to the source population at Taunton.

Dr Rachel Ladd, AWC Wildlife Ecologist declared the translocation a success. “It was a massive effort, but the team secured the number of wallabies we set out to capture.”

The Bridled Nailtail Wallaby was reintroduced to Scotia in 1998, initially as part of a captive breeding program operated by the previous owners Earth Sanctuaries Limited. After AWC acquired the property in 2002, Scotia’s conservation fences were upgraded and expanded to the current 8,000-hectare safe haven (made up of two adjoining 4,000-hectare fenced areas or ‘stages’), with all feral predators eradicated. This enabled ecologists to release 162 wallabies from the breeding program inside Stage 1 in 2004-2005, and then another 267 individuals inside Stage 2 in 2008.

Populations within both areas increased rapidly after high rainfall in 2010-2011 and remained stable until 2018, when the lower Murray Darling region experienced its severest drought conditions in over 120 years. Populations declined, hitting a low of 70 individuals across both stages in 2020, which led to AWC to combine all remaining wallabies into Stage 2 to limit inbreeding.

In May 2024, the population in Stage 2 was estimated at 1,686 individuals, thanks to wetter weather conditions. The population within Stage 1 remained relatively low, with an estimated 88 individuals.

“Native animals such as the Bridled Nailtail Wallaby undergo natural cycles of boom and bust in response to prevailing conditions,” Dr Ladd explained. “The recent drop in Bridled Nailtail Wallaby numbers at Scotia presented an opportunity for us to enhance the genetic diversity of the population without requiring a large number of new animals.”

“We consulted geneticist Dr Andrew Weeks who advised us to release the Taunton individuals into Stage 1, and we will look into integrating the wallabies across both stages over time.”

Following their specially chartered flight from Taunton to Scotia, the wallabies were released inside the feral predator-free area. Most individuals were fitted with tracking collars which will be used to monitor their progress in the new environment over the next 12 months.