Greater Bilby Populations Increase Fourfold in Australian Sanctuaries Since 2021

The Australian Wildlife Conservancy conducted a census recording 5,330 greater bilbies across six sanctuaries in the Northern Territory, Western Australia, South Australia, and New South Wales. This represents a fourfold increase from 2021 levels, according to the organization.

Greater bilbies, also known as Easter bilbies, once occupied three-quarters of Australia but declined due to colonization and introduced feral predators, as stated by the federal government. The species is classified as threatened. Conservation efforts by the non-profit Australian Wildlife Conservancy involve reintroductions and habitat management in fenced, predator-free areas.

At Newhaven Animal Sanctuary in the Northern Territory's Tanami Desert, 66 bilbies were released in 2022, and the population has grown to 530. The site, a former cattle station converted to a 9,450-hectare conservation area located 350 kilometers northwest of Alice Springs, excludes predators through fencing. This census marks the first population estimate since the reintroduction.

In Mallee Cliffs National Park in New South Wales, the bilby population reached 1,840 individuals following the release of 107 bilbies between 2021 and 2023. Similar management practices, including fire control, weed removal, and fence maintenance, support these populations.

Recent years of above-average rainfall have increased food availability, reducing the need for bilbies to dig extensively. Newhaven wildlife ecologist Tim Henderson attributed the growth to the absence of predation from feral cats and foxes, combined with abundant resources.

“The abundance of resources and a landscape that has no predation pressure from feral cats or foxes has really allowed them to just pretty much go nuts," Dr. Henderson said.”

Bilby diggings aerate soil and promote seed germination, enhancing vegetation diversity, according to Dr. Henderson. This benefits other species, such as the burrowing bettong, which expand bilby burrows into communal warrens supporting up to 15 or 20 individuals.

Dr. Henderson noted that the Newhaven population may decline during the next drought but is positioned to recover afterward. The Australian Wildlife Conservancy plans to continue monitoring and management to sustain these populations amid environmental challenges.