Bilby
The greater bilby was once widespread across arid and semi-arid regions of Australia. Today, this threatened native mammal is listed as extinct in the wild in NSW, but reintroduction efforts are seeing bilbies bounce back.
Heading towards extinction
For thousands of years, the greater bilby (bilby) roamed across Australia’s arid, semi-arid and temperate regions. Around 80% of Australia was once bilby country.
The double-whammy of widespread habitat loss due to land clearing, and introduced species like cats and foxes, have devastated bilby populations over the past 100 years.
While bilbies evolved and adapted to native predators, like snakes, quolls, and monitor lizards, they’re easy pickings for introduced hyper-predators like cats and foxes. Competition from rabbits is another pressure facing struggling bilby populations.
Since the early 20th century, the bilby has been extinct in the wild in NSW. But, thanks to recent reintroduction efforts NSW is again home to the greater bilby.
Let me (re)introduce you
NSW National Parks and Wildlife Service (NPWS) is working with Australian Wildlife Conservancy (AWC) and the University of NSW Sydney (UNSW), to establish specially constructed, feral predator-free fenced enclosures.
Perhaps better known as ‘exclosures’, these high-security wild-area management zones exclude 100% of feral predators.
With help from breeding programs, and wild remnant populations in south-west Queensland and north-west Australia, bilbies have successfully been reintroduced to feral predator-free areas in Sturt National Park, Pilliga State Conservation Area, and Mallee Cliffs National Park.
The feral predator-free safe havens include native plants and animals that call these arid or semi-arid habitats home. They also offer opportunities to reintroduce other regionally extinct or endangered species that historically formed a critical part of the ecosystem, including former wild native predators like the western quoll.
4 facts about the bilby
1. Bilby babies
Bilbies have one of the shortest gestation periods of any mammal – around 12–14 days. The tiny joeys are underdeveloped when born and stay in their mother’s pouch for several months until they’re fully formed.
Like other burrowing marsupials, the female bilby’s pouch faces backwards, to stop it from getting filled with dirt while she’s digging.
2. Water saving adaptations
Bilbies don’t need to drink water. Their diet of insects, tubers, seeds, roots, bulbs and fungi not only also satisfies their food needs but gives them all their water requirements.
With their large, rabbit-like ears the bilby has become a popular Aussie icon at Easter. Their ears are full of capillaries that cool their blood and prevent the need to sweat. These adaptations help bilbies to survive in some of Australia’s relentlessly dry landscapes, where there’s no reliable water.
3. Safe havens for many species
The feral predator-free exclosures in Sturt National Park, Pilliga State Conservation Area and Mallee Cliffs National Park, have also benefited other species.
Researchers have observed that mallee fowl, painted buttonquail and yellow-footed antechinus are also rebounding thanks to these safe havens, and a return to a life free from introduced predators.
4. Evolution accelerated
Most attempts to reintroduce bilbies outside fenced refuges have ultimately ended in failure. They get eaten faster than they can reproduce. To help evolutionary natural selection processes, researchers are exposing some bilbies to low levels of feral cats to speed up predator evasion behaviours. Early results are positive, with bilbies becoming increasingly vigilant and reacting faster to cats.
Animal facts
- Common name
- Bilby
- Scientific name
- Macrotis lagotis
- Conservation status in NSW
- Presumed extinct
Ecological engineers
Bilbies are nocturnal animals, spending their days resting in deep spiralling burrows. The deep network of tunnels can be up to 2m deep, providing protection from weather extremes as well as predators. After sunset, they emerge to forage for insects, bulbs, fruit, fungi, seeds and even very small mammals.
Unlike bandicoots, bilbies are expert diggers. A single bilby can excavate several tonnes of soil each year – more than other animals in their habitat. They’re considered to be ecological engineers. Their presence in the landscape can affect the entire ecology, as their digging helps to aerate and increase water infiltration in sun-baked soils, recycling leaf litter nutrients and burying seeds in perfect conditions for germination.
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