Australian Wildlife Conservancy (AWC) has reintroduced the Bilby to south-western Australia – returning this threatened species to the region for the first time in several decades through an initial translocation of 16 Bilbies from AWC’s Scotia Wildlife Sanctuary (NSW/SA border) to Mt Gibson Wildlife Sanctuary (WA).Read more...
Range and abundance
At the time of European colonisation, Brush-tailed Bettongs inhabited much of southern Australia, from Western Australia through to the western plains of the Great Dividing Range in New South Wales and southern Queensland. Two sub-species are recognised – the Brush-tailed Bettong (Bettongia penicillata penicillata) in eastern Australia and the Woylie (B. p. ogilbyi) in Western Australia. However, the historical geographical relationship of these sub-species is uncertain and their common names are used interchangeably.
Due to extensive range contraction and population decline, B. p. penicillata is now presumed extinct, whilst B. p. ogilbyi is restricted to three remnant populations in southwest Western Australia - Dryandra Woodland, Tutanning Nature Reserve and Perup Forest. Conservation efforts have resulted in the establishment of a number of reintroduced populations including AWC’s Karakamia, Scotia and Yookamurra sanctuaries.
The Woylie is a small marsupial with greyish-brown fur on the upperparts and flanks and pale grey fur on the underside. The tail is darkly coloured with a distinctive black brush at the end (hence the species’ common and scientific name). Adult males grow to 36 cm (head-body) and 1.8 kg. Females are slightly smaller than males.
Woylies are nocturnal and forage primarily for underground fungi (truffles), but also feed on tubers, bulbs, seeds and other vegetative products, such as resin. They can store food items in their cheek pouches for later caching or eating. As a result, Woylies contribute significant ‘ecological services’ to areas they inhabit, as they disperse plant seeds and fungal spores. Their diggings also increase water infiltration to the soil, and allow seeds and organic matter to be trapped, facilitating plant recruitment. During the day, Woylies retreat to simple nests that are constructed from long grasses or bark. Nests are located on the ground in or near thickets of vegetation, spinifex hummocks, small shrubs or grass-tree fronds.
Females breed continuously throughout the year, giving birth to one young (rarely two) at a time. A single female can produce up to three offspring per year, depending on environmental conditions. Joeys remain in the pouch for 90 - 110 days.
The Woylie population has declined from 225,000 to between 10,000 – 20,000 in the last 15 years. Predation by European foxes is the major cause of range contraction and decline of Woylie populations. However, predation by feral cats is emerging as another serious threat. In Western Australia, Woylies increased in distribution and abundance following large-scale fox-baiting during the 1980s; however, most populations have declined again in the last decade. The most likely cause is predation by feral cats, although research is also being conducted into the potential role of disease in population decline. In the past, extensive areas occupied by the Woylie were cleared for agriculture, and millions of Woylies and other bettongs were killed as agricultural pests or for the fur trade in the early 20th century.
What is AWC doing?
AWC protects almost 10% of the world's remaining Woylie population. AWC supports important populations of Woylies within predator-proof fenced areas on Karakamia, Scotia, Yookamurra and Mt Gibson sanctuaries. The Karakamia population has the distinction of being the only population of Woylies in Western Australia that has not declined in recent years. AWC ecologists monitor populations of the Woylie on the four sanctuaries where it occurs. AWC contributes to the national Woylie Recovery Team, and facilitates a number of research projects that are investigating the causes of population decline.