Community / 18th June 2020
Bilby project reaches historic milestone in Pilliga
The regionally extinct Greater Bilby has made a successful return to the Pilliga Forest.
The key to successfully reintroduce the Bilby into the Pilliga has been the establishment of a massive feral predator-free area that is allowing the gradual addition of native species that have been extinct in the area for more than 100 years.
The project is a strategic partnership between NSW National Parks and Wildlife Service and Australian Wildlife Conservancy (AWC) ‘Reintroduction of Locally-extinct Mammal Species’ as part of NSW Government ‘Saving our Species’ program.
The first of the Bilbies were initially released into a 680-hectare fenced area within a 5800-hectare feral predator-free fenced area near Narrabri in 2018.
This release was followed by the introduction of Bridled Nailtail Wallabies in 2019. Both reintroductions were historic occasions for the AWC and the NSW government.
“The aim of building these feral predator-free areas is to reintroduce and establish viable populations of locally extinct mammals that were once found naturally in the region,” said Greg Holland, Senior AWC Wildlife Ecologist.
“Unfortunately, Australia has the worst mammal extinction rate in the world, and many native mammals, such as the Bilby, have become locally extinct.
“We plan on bringing six of those species back to the Pilliga Forest.”
AWC staff from across southern Australia were involved in the complex translocation effort. A team of more than 20 ecologists were deployed spotlightingand catching Bilbies, the source population for the relocation.
“Bringing the animals to the Pilliga has had its challenges,” Mr Holland added.
“We had to source healthy animals and move them across the country.
“The Bilbies were brought from AWC’s Scotia Sanctuary, in far western NSW, and from Thistle Island in the Spencer Gulf, South Australia. They were flown to Narrabri and then transported to the fenced area in air- conditioned vehicles.
“One of the biggest challenges we face is removing all feral predators, such as cats and foxes, from inside the conservation fence.
"This requires a lot of time and effort, and ongoing continual monitoring to ensure no feral predators find their way in.
“Bilbies were fitted with radio transmitters in the first three months after they were released to allow their movements and survival to be monitored. We also have remote cameras permanently deployed to allow ecologists to keep track of them.
“We also conduct trapping every six months to assess the population size, animal health and to see if they have reproduced.”
The Greater Bilby is an iconic Australian marsupial, instantly recognisable by its long, pointed snout, long ears, soft grey fur and striking black and white tail. Using their strong forelimbs, Bilbies dig burrows up to three metres long to live in.
They are opportunistic feeders, with a broad diet consisting of insects, seeds, bulbs, fruit and fungi. Bilbies act as important ‘ecosystem engineers’; in the course of digging burrows and feeding, an individual Bilby turns over up to 20 tonnes of topsoil in a year.
AWC protects almost 10 per cent of the entire Bilby population, but with ongoing translocations, this figure is set to double in the coming years.
“We have successfully reintroduced Bilbies to five feral-free areas, and more translocations are planned,” Mr Holland said.
“Indicators of success are when the reintroduced Bilby population increases in size and becomes self-sustaining.
“Another indicator is when other locally extinct mammals are also successfully reintroduced. Reintroduced mammals establish important ecological processes, such as digging and turning over the soil, so the ecological health of the forest is improved.
“Results will be published in coming years as reintroduced populations become established.
“Allowing access to members of the public is part of the plan, but first we need to ensure the viability and safety of the populations of the returned mammal species and their habits.”
NPWS Castlereagh Area manager, John Whittall said that at a local level it is exciting to be part of the ground breaking program.
“For us to be able to reintroduce mammals that once lived in the area back into this landscape is so rewarding, with benefits for wider park ecosystems,” Mr Whittall said.
“The burrowing and other activities of the mammals will also promote healthy vegetation by retaining water and nutrients and helping seed dispersal. In addition, removal of introduced predators will benefit a range of other species, particularly ground-dwelling and ground-nesting species.”