The bilby, an iconic Australian marsupial, has distinctive features like long ears, a bandicoot-like body, and a pointed snout. These nocturnal animals are adept burrowers, creating deep spiraling tunnels for shelter from heat and predators. Bilbies inhabit the arid and semi-arid regions of Australia, primarily in central and northwestern deserts, and parts of southwestern Queensland. As ecosystem engineers, their digging habits aerate soil and disperse seeds.
Bilby Population Today
The Greater Bilby, Macrotis lagotis, is classified as Vulnerable nationally, listed as Endangered in Queensland, and presumed extinct in New South Wales. The Lesser Bilby, Macrotis leucura, a smaller relative, became extinct between 1931 and 1960. Once widespread across approximately 70% of mainland Australia, the Greater Bilby’s range has contracted significantly, now occupying only about 20% of its historical distribution.
Estimating wild bilby numbers is challenging due to their elusive, nocturnal nature and scattered populations. Fewer than 10,000 individuals remain in fragmented wild populations. Recent conservation efforts provide more specific counts within protected areas. For instance, an April 2023 census reported an estimated 3,315 Greater Bilbies across six Australian Wildlife Conservancy (AWC) protected sanctuaries, a substantial increase from 1,480 individuals in 2022. These managed, fenced reserve populations represent a significant portion of the species’ current numbers.
Factors Threatening Bilbies
The significant decline in bilby numbers stems from several interacting factors intensified since European settlement. Predation by introduced species is a significant threat. Feral cats and red foxes, introduced to Australia, are highly effective hunters that prey on bilbies, falling within their preferred prey size range.
Habitat loss and degradation also significantly contribute to their vulnerability. Land clearing for agriculture, mining, and human development has reduced and fragmented bilby habitats. Altered fire regimes, with frequent, intense wildfires, further diminish suitable habitat and food sources, leaving bilbies more exposed to predators.
Competition for resources with introduced herbivores exacerbates challenges for bilbies. Rabbits, cattle, and sheep compete directly with bilbies for food, like grasses, seeds, and plant matter. This competition, coupled with soil degradation from grazing livestock, reduces essential food plants and can render areas unsuitable for bilby burrowing. Prolonged droughts further limit food and water availability, intensifying competition among species.
Protecting Bilbies for Tomorrow
Conservation efforts for bilbies focus on mitigating threats and restoring populations. A primary strategy involves establishing predator-free fenced enclosures, known as “safe havens” or “exclosures.” These large areas, managed by organizations like the Australian Wildlife Conservancy and Taronga Conservation Society Australia, are cleared of introduced predators (cats and foxes), providing secure environments for bilbies to breed and thrive.
Reintroduction programs expand bilby distribution within these safe havens and into suitable areas within their former range. Bilbies are often sourced from captive breeding programs, carefully managed for genetic diversity. These captive-bred individuals are then released into predator-controlled environments, like Currawinya National Park, Scotia Wildlife Sanctuary, and Newhaven Wildlife Sanctuary.
Beyond fenced areas, targeted predator control programs reduce feral cat and fox numbers in broader landscapes. Strategic burning practices also manage vegetation, create firebreaks, and promote food plant growth, reducing destructive wildfires. Ongoing research and monitoring of bilby populations, including surveys and tracking, help understand their ecology and adapt management strategies. Community involvement and education initiatives, like the “Easter Bilby” campaign, also raise public awareness and support.