Range and Abundance
The Western Barred Bandicoot was once found across much of southern Australia in the arid and semi-arid zones. The first Western Barred Bandicoot sighting was recorded in 1817 on the Peron Peninsula in Western Australia where they were considered to be common. A little over 100 years later, the last Western Barred Bandicoot became extinct on the mainland. Since then it has been confined to Bernier and Dorre Islands in Western Australia. It has also been successfully reintroduced to a few protected sites on the mainland.
The Western Barred Bandicoot shelters during the day in a nest. It constructs this by digging a shallow hollow under a shrub, and filling it with leaves and sticks. A single small entrance hole is made to enable it to get in and out. The hole is disguised from predators using leaves. Some Western Barred Bandicoots will use the same nest over the course of the week, while others will move to a new nest each night. If caught out in the open a Western Barred Bandicoot will use another animal’s burrow to shelter in until the threat has gone away.
A bandicoot nest under a shrub. Photo by Caitlin Weatherstone.
Although not as adept at digging as its cousin the Bilby, the Western Barred Bandicoot uses its strong hind legs to dig below the ground to forage for insects, spiders and worms. It also eats seeds, roots, herbs and other smaller animals. It uses its good sense of smell to detect food up to 30 cm underground.
In 1886 an early naturalise Gerard Krefft described the Western Barred Bandicoot as being excellent at catching mice. “They would tumble the mice about with fore paws and break their hind legs.” The Western Barred Bandicoot could kill up to 20 mice with astonishing speed.
Western Barred Bandicoots will only breed after heavy falls of rain. Two or sometimes three joeys are born at a time. The Western Barred Bandicoot has one of the shortest gestation periods of any mammal of 12.5 days. When the babies are first born, they are only 10 mm long and weigh as little as a quarter of a gram (about the size of a tic tac). The pouch is backward opening so that when digging, the dirt is not thrown into the pouch. The pouch contains eight teats so that the next litter of young can use alternate teats as it takes a month for a teat to return to normal size after a joey has been weaned. This means a bandicoot can have quick, successive litters. Young stay in the pouch for 45 – 60 days and after two weeks outside the pouch the young bandicoot is independent of its mother.
The extinction of Western Barred Bandicoots from the mainland has largely been due to predation by cats and foxes. Other factors include changes in fire regimes and grazing by stock and rabbits. The Western Barred Bandicoot is now listed nationally as Endangered with less than 3000 individuals left in the world.
Another threat to the Western Barred Bandicoot is a Papilloma wart virus found in some captive and wild animals. It was discovered on a captive bred Western Barred Bandicoot in 1999. The wart virus, in severe cases, can cause blindness and an inability to walk due to severe warts and lesions on the animal’s feet. The first bandicoots reintroduced to Arid Recovery had to spend some months in quarantine to ensure they were disease-free before being released into the reserve.
What is Arid Recovery Doing?
In September 2000, 11 Western Barred Bandicoots were transported from Bernier Island in Western Australia and released into a pen in the Main Enclosure at Arid Recovery. This is the only place outside of Western Australia where Western Barred Bandicoots are found. There are now an estimated 500 individuals in the Reserve.
Initially, breeding success was stimulated by providing water within a soft-release pen. As a result, females were able to bear a second litter of young in the first season of the trial.We had concerns for inbreeding, as animals were sourced from one location only. So, in September 2009 a long awaited supplementary release of 5 individuals from Faure Island in WA (managed by the Australian Wildlife Conservancy) was conducted to expand the genetic stock and increase the viability of the population.
A Western Western Barred Bandicoot added to Arid Recovery from Faure Island, to improve genetic diversity. Photo by Ben Parkhurst
Mixing the two source populations had the desired effect. A recent study by Lauren White has compared the genetic diversity of the current Western Barred Bandicoot population in the reserve to the genetic samples that were taken from the founding population over 15 years ago. Amazingly the genetic diversity of the current population of Western Barred Bandicoots is now slightly greater than the founding population and genetic material from both populations has been retained.
Written by Rachael Loneragan (March 2017)