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Species Fact Sheet: Greater bilby © WWF, KLEIN & HUBERT Greater bilby Macrotis lagotis The greater bilby is an iconic threatened marsupial that historically occurred across 70 per cent of continental Australia but has declined dramatically since European settlement. Now it is restricted to drier desert areas in the Northern Territory and Western Australia and to a small corner of south western Queensland and is being reintroduced to selected locations in South Australia and New South Wales. The species is culturally important to many Indigenous people, and was formerly a valuable food resource. Bilbies are about the size of a small cat and have soft, blue-grey fur with white under parts and a distinctive white-tipped tail. They have long, highly sensitive ears and a pointed snout. Their forelimbs have three clawed toes and two un-clawed toes that enable them to burrow effectively. Mature males tend to weigh double that of mature females and have longer canines and a noticeably enlarged forehead. Conservation status The World Conservation Union (IUCN) Redlist of Threatened Species: Vulnerable Australian Government - Environment Protection and Biodiversity Conservation Act 1999: Vulnerable Did you know? • The greater bilby is the only surviving member of the sub-family Thylacomyinae (family Peramelidae). • In captivity, bilbies have been known to live up to 10 years of age. • Despite their sharp sense of hearing and smell, greater bilbies have relatively poor eyesight. Distribution and habitat Most bilbies live in sandy desert areas in spinifex (Triodia species) grasslands. They dig large burrows up to two metres deep in sandplain country, where they live either singly or in pairs. They also seem to favour freshly burnt country where there are more plentiful supplies of preferred foods. According to the National Recovery Plan, bilbies live among three major vegetation types: • Open tussock grassland (both grasses and forbs) growing on uplands and hills, • Mulga woodland/shrubland (both pure mulga and mixed stands of mulga/witchetty bush) growing on ridges and rises, and • Hummock grassland growing on sand plains and dunes, drainage systems, salt lake systems and other alluvial areas. Currently there are two distinct geographic areas occupied by bilbies. One extends from the western deserts region (Tanami, Great Sandy, Gibson) of the Northern Territory and Western Australia west to the Pilbara. The second is in the channel country of south west Queensland. Ecology and life cycle Bilbies forage mostly at night. They like to eat a mix of plant food (bulbs and seeds) along with termites, ants, beetles, insect larvae, witchetty grubs and spiders, most of which they dig up with their strong front legs. One of the bilby’s favourite plant foods is the bush onion or yalka (Cyperus bulbosa) that grows in desert sandplains after fires. The bilby uses its long thin tongue to lick food from the ground, which results in up to 90 per cent of its waste being made up of sand. A bilby burrow does not appear to contain a nest chamber or any nesting material; instead it is used mainly for shelter during daylight hours and intermittently at night for rest and refuge from predators and temperature extremes. Within its home-range a single bilby may have over a dozen regularly used burrows, some of these containing multiple entrances. The greater bilby appears to have a polygamous mating system where sexually mature males mate with multiple females. Females have a backward opening pouch with eight teats. A healthy female can produce four litters per year with one to three young to a litter. Gestation takes around 14 days, then the young remain inside the pouch for approximately 75–80 days. After emerging from their mother’s pouch the young remain in the burrow for about two weeks while the adults return regularly to feed them. Threats Predation Feral cats and foxes, wild dogs and dingos are known to prey on both young and adult bilbies. The risk of predation is thought to be greater following large wildfire events when bilbies have to range further from home burrows to search for food. By looking for residual hair from native mammals in the scats of cats and foxes it is possible to measure the impact they are having on our native species. Recent research in the Tanami Desert has shown bilby fur in roughly three per cent of the cat scats examined. It seems remaining bilby populations in some desert areas are able to persist alongside fairly high levels of foxes and cats, probably as a result of favourable fire regimes in the region. These regimes can create enough high-quality food resources so bilbies do not need to spend long hours above ground looking for food. Competition with introduced herbivores Bilbies are forced to compete with introduced species such as camels, cattle and rabbits. These species compete for food resources as well as damaging the soils where burrows are located. Camels occur throughout the range of bilbies whereas cattle are more restricted in their impact (in Queensland only). Unsuitable fire regimes Some of the vegetation making up a large portion of the greater bilby’s diet appears to rely heavily on the incidence of fire to regenerate. Large uncontrolled fires may eventually reduce the type and abundance of food plants available to the bilby. Drought & climate change The greater bilby is only partly adapted to arid environments and thus could be at risk of local extinctions during severe droughts. Changing weather conditions brought about by climate change also have the potential to negatively affect the bilby’s food sources, further adding to the decline of populations. Conservation Action There are many recovery projects in progress. These include breeding bilbies for release into fenced areas or predator-free islands at Venus Bay and Roxby Downs in South Australia, Uluru-Kata Tjuta National Park in the Northern Territory, Shark Bay and Dryandra Woodland in Western Australia, and Currawinya in Queensland. Aboriginal people in the Gibson and Great Sandy Deserts in Western Australia and the Northern Territory’s Tanami Desert are working alongside scientists and Land Council staff to survey and monitor wild bilby populations. Western Australia’s Department of Conservation and Land Management is also developing fox and cat baiting methods and running baiting trials in several bilby habitat areas across the country. In addition the Australian Government recently launched National Bilby Day, which is held annually on the second Sunday in September to raise awareness about the plight of bilbies and other threatened species. How you can help • Contact the Save the Bilby team and donate your time (if you live in southern Queensland) or to make a financial contribution at www.savethebilbyfund.com • Protect remnant bush in your community or on your land to help provide habitat for all our native animals, including the bilby • Support National Bilby Day WWF-Australia GPO Box 528 Sydney NSW 2001 Tel: 1800 032 551 wwf.org.au © 1986 Panda symbol WWF. ® (trademark words, e.g. “WWF”, “panda”, or “living planet”) is/are WWF Registered Trademark/s.