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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
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