By Dr Rod Kavanagh, Senior Ecologist
A remarkable milestone was reached in December 2018 when, as part of the NSW Government’s Saving Our Species program, AWC restored Bilbies to a NSW National Park, more than a century after going locally extinct. Their return to the public estate is a powerful demonstration of our ability to turn back the tide of extinctions in Australia. Now, early monitoring results indicate that these iconic Australian mammals are adapting to their new environment.
The first ever translocation of locally extinct Greater Bilbies (Macrotis lagotis) to the Pilliga forests of NSW involved the release of sixty Bilbies (28 males, 32 females) into a specially-constructed fenced area, safely tucked into the 5,800 hectare feral predator-free zone. Half of the Bilbies were sourced from AWC’s Scotia Wildlife Sanctuary with the remainder coming from Thistle Island, off the coast of South Australia. Geneticists from the University of Sydney confirmed this mix of source populations would deliver the best genetic diversity in the new Pilliga population.
All 60 Bilbies were fitted with uniquely numbered microchips to allow for individual identification and VHF radio-transmitters were attached to the tails of 35 animals (21 males, 14 females) so their survival, movements and behaviour could be monitored in the weeks immediately following release. A subset of Bilbies also received detailed health examinations by a veterinary team from Sydney’s Taronga Zoo.
As dusk fell, each Bilby was safely released into the fenced predator-free area. AWC ecologists have since been monitoring their progress through a combination of spotlighting, trapping and remote cameras. Seven Bilbies were recently detected by spotlighting, and a further four were trapped over four nights. Despite prevailing hot and dry conditions, all the recaptured animals had put on weight and were in good condition.
Among the animals trapped during the survey was a new female Bilby that was possibly a pouch young at time of release, the first recorded in a NSW national park in more than 100 years.
The Bilbies have settled well into their new environment, within days each digging a burrow (up to three metres deep) in the sandy soil. Interestingly, most burrows were initially dug in open clearings similar to those used at the less-forested source locations (Scotia, Thistle Island). However, it became evident that the Bilbies soon became more selective with regard to where they dug burrows, choosing locations such as under large logs and other fallen timber. The landscape has been quickly transformed by small foraging pits and burrows – the Bilbies living up to their moniker of ‘ecological engineers.’
This frenetic activity by our native diggers has not been seen in a national park for more than 100 years. Bilbies were last seen in NSW in 1912. Once widespread across much of Australia, predation by feral cats and foxes and competition with feral herbivores, like rabbits, have seen Bilby populations collapse.
AWC’s network of fenced safe-havens, now protect 15 per cent of the global population of Bilbies and are providing important source populations of Bilbies for rewilding efforts, like this one in the Pilliga. To highlight the significance of this initiative, the Bilby population in the Pilliga is projected to grow to an estimated 850 animals – equivalent to almost 10 per cent of the current Australian population.
Returning extinct mammals to NSW National Parks
Our historic partnership with the NSW Government will see at least five other regionally extinct mammals reintroduced to the Pilliga in the next two to three years, making it one of the nation’s most important endangered species projects. The five animals are the Bridled Nailtail Wallaby, Brush-tailed Bettong, Western Barred Bandicoot, Plains Mouse and Western Quoll. The feral predator proof fence will also protect extant mammals including the Eastern Pygmy Possum and Pilliga Mouse, and threatened bird species including Bush Stone Curlew and Speckled Warbler.
Next steps: building a field-operations base
The NSW Government is investing over $40 million as part of the Saving our Species program to establish three predator-proof fenced areas, two of which are being developed and managed by AWC. Under the partnership model, the Government is contracting AWC to establish large feral predator-free havens at Mallee Cliffs and the Pilliga, as well as to implement a framework for measuring ecological health and deliver conservation land management at each national park. As our contribution to the partnership, AWC is now focused on constructing a dedicated field-operations base for AWC staff working on-site. This on-ground infrastructure is critical for building on our capacity to deliver a world-class science program (AWC undertakes 15,000 trap nights every year in the Pilliga) and practical land management services, such as feral animal control, across 35,000 hectares of the Pilliga.
We need your help to construct a field-operations base for AWC staff in the Pilliga. $500 will help purchase building supplies. Please make a tax deductible donation to help save endangered mammals and roll out this exciting new model for conservation.