Quolls, Bilbies, and Bandicoots: What Is Actually Being Done to Save Small Native Mammals

Australia's record on mammal extinction is the worst of any country in the world. Since European settlement, more than 30 mammal species have been lost entirely — a rate of extinction that has no parallel in the modern conservation record of any other nation. The species that have disappeared are disproportionately the small to medium-sized mammals: the macrotis, the peramelids, the dasyurids. The animals that bounce, dig, and scurry through the understorey. The ones that most Australians have never seen.

The causes are well established and genuinely depressing in their familiarity: introduced predators — primarily the red fox and the feral cat — combined with introduced herbivores that degrade habitat, altered fire regimes that remove the structural complexity these animals require, and in many cases direct land clearing. None of this is new knowledge. What is less well understood, and more worth discussing, is the genuine progress being made in specific areas and the complexity of the problems that remain.

The Species at the Centre of It

Quolls — Australia has four species, the spotted-tailed, eastern, western, and northern — are carnivorous marsupials whose decline across their former ranges tracks almost precisely the expansion of fox and cat populations. The spotted-tailed quoll, the largest of the four, was once found throughout the eastern seaboard from northern Queensland to South Australia; it is now locally extinct across enormous portions of this range and survives in reasonable numbers only in Tasmania, which has no feral cats established at ecologically significant densities and no foxes — the result of decades of vigilance at ports of entry. On the mainland, spotted-tailed quolls persist in remnant populations in the highland forests of Victoria, NSW, and south-east Queensland, but the populations are fragmented and small.

Bilbies are perhaps the most culturally visible of Australia's threatened small mammals — the Easter bilby campaign has made them genuinely famous — and among the most ecologically specialised. Their enormous ears and long, pointed snouts are adaptations for life in arid Australia: the ears dissipate heat and detect movement underground, the snout is built for digging out the bulbs, fungi, invertebrates, and small vertebrates that constitute their diet. Greater bilbies have been extinct from 80 percent of their original range, including all of New South Wales, Victoria, and South Australia, since the late 19th and early 20th centuries. They survive in parts of Queensland, Western Australia, and the Northern Territory — primarily in areas where fox and cat densities are low due to distance and inhospitable terrain.

Bandicoots include several species in varying states of decline. The eastern barred bandicoot was functionally extinct on the Australian mainland by 1990, surviving only in Tasmania; a reintroduction program in Victoria using fox-free fenced sanctuaries has re-established mainland populations. The western barred bandicoot is restricted to Dorre and Bernier Islands in Shark Bay, Western Australia, and a small fenced mainland enclosure. The southern brown bandicoot clings to pockets of coastal heath in south-eastern Australia, under sustained predator pressure. The pig-footed bandicoot — a remarkable, deer-like animal whose forefeet bore two functional toes like a small ungulate — is simply gone, extinct in the 1950s with minimal documentation of its ecology and behaviour.

The Predator Problem in Full

Understanding why these animals decline requires understanding what cats and foxes actually do to small mammal populations, because the mechanism is counterintuitive in its efficiency.

Small marsupials evolved in an environment with few cursorial predators — the thylacine was the largest mammalian predator in the system, and it hunted primarily large prey. The arrival of the red fox and the domestic cat (which feral cats descend from) introduced predators with hunting behaviours, sensory capabilities, and population dynamics that Australian fauna had no evolutionary experience with. Native animals do not recognise the smell of a fox as a threat signal in the way that European rabbits do; they have not evolved flight responses triggered by cat scent; their reproductive rates were calibrated to a lower predation regime.

The result is predation that can functionally extirpate a small mammal population from an area before the animals have adapted or the population has crashed to the point where it becomes self-limiting. A single feral cat in productive habitat can kill between five and fifteen small mammals per night; population estimates for feral cats across Australia range from two to six million animals, with the number fluctuating dramatically in response to rainfall and prey availability. Following a good season that inflates rabbit populations, cat numbers build, and when the rabbit population crashes, cats switch to native fauna with devastating efficiency.

What Is Actually Working

Against this context, a number of approaches have demonstrated genuine effectiveness.

Fenced predator-free sanctuaries are the most reliably successful intervention in Australian small mammal conservation. By excluding foxes and cats through continuous fencing — typically a low-set wire mesh with an outward-leaning overhang that prevents climbing — and then systematically eliminating any predators that establish inside, these sanctuaries create areas where small mammals can maintain populations without predation pressure. The Australian Wildlife Conservancy operates over 30 sanctuaries of this type across the country; the Arid Recovery Reserve in South Australia, established in 1997, is one of the longest-running examples and has demonstrated sustained population recovery of bilbies, burrowing bettongs, and greater stick-nest rats within its boundaries.

The limitations of sanctuaries are real: they protect the populations inside them from predation but don't address the causes of decline in the surrounding landscape, they are expensive to build and maintain, and the populations within them are effectively isolated from the broader metapopulation processes that maintain genetic diversity over time. They are a holding strategy — essential and valuable, but not a solution.

Island refuges play a complementary role. Offshore islands that have never had foxes or cats, or from which these predators have been eradicated, provide genuinely wild habitat where small mammals can maintain large, self-sustaining populations. Remarkable results have been achieved in Western Australia's Shark Bay islands, on Boullanger and Kangaroo Islands, and on a number of smaller islands that have been subject to eradication programs. The Kangaroo Island dunnart — a tiny carnivorous marsupial considered critically endangered before the 2019-20 bushfires reduced its known population by perhaps 90 percent — is now the subject of an intensive island-based recovery program that represents one of Australia's most urgent conservation efforts.

Landscape-scale predator management using 1080 baiting programs reduces fox and cat densities across large areas of public land, with documented positive responses in native fauna at the landscape scale. The effectiveness is real but conditional — ongoing investment is required, density rebounds quickly when baiting stops, and cats are significantly harder to bait than foxes because of their dietary preferences and wariness.

Introduced predator behavioural modification — specifically, training native animals to recognise and respond to fox and cat scent — is an emerging field with intriguing preliminary results. Animals raised in predator-free environments and subsequently released into areas with predators show very high initial predation rates. Programs that expose animals to predator cues during rearing, or that release into areas with low predator density and allow gradual exposure, show improved survival.

The Honest Assessment

It would be dishonest to present the state of Australian small mammal conservation as anything other than a crisis that is being managed with partial tools. The fenced sanctuaries are genuine successes but their total area is a tiny fraction of the habitat that has been lost. The island refuges are real but vulnerable to a single introduction event — a cat or fox reaching an island refuge by swimming, boat, or deliberate introduction has the potential to unravel decades of recovery work. The predator management programs are valuable but expensive and impermanent.

The deeper problem is political and economic: the scale of intervention required to reverse small mammal declines across the Australian continent is genuinely enormous, and the funding committed to it is genuinely insufficient. Feral cat management alone — one component of the problem — would require a national commitment comparable to major infrastructure investment.

What is being done is real, important, and worth knowing about. The organisations doing it — the Australian Wildlife Conservancy, the Arid Recovery partnership, Rewilding Australia, and dozens of smaller regional groups — deserve both financial support and public attention. But clear-eyed optimism requires acknowledging what the current trajectory produces, and adjusting the response accordingly.

How Individuals Can Help

This is a question worth answering directly, because the conservation literature tends to describe institutional interventions and leave individuals feeling passive in the face of systemic problems.

The most direct individual contribution is financial support to organisations operating predator-free sanctuaries and recovery programs. The Australian Wildlife Conservancy and Arid Recovery both accept donations that go directly into operational conservation work — fencing, predator control, animal monitoring, and breeding programs. These are not abstract advocacy organisations; they are field operations with measurable outcomes, and additional funding produces additional outcomes.

Cat management at the property scale is meaningful in rural and peri-urban areas. Keeping domestic cats indoors at night, supporting local council trap-neuter-return programs, and managing vegetation around homes to reduce cover for feral cats around residential fringes all reduce predation pressure at the landscape level. Individual actions don't reverse a national crisis, but a million individual actions in aggregate constitute a landscape-level change.

Supporting policy that enables predator management on public land — including the politically uncomfortable conversation about intensive feral cat management — is perhaps the most scalable contribution available to concerned citizens. The animals are charismatic. The problem is solvable, in principle. The solution requires will as much as it requires technique.