Social lives of bilbies more complex than previously thought

New bilby research reveals more about the social lives of these small, covert creatures, offering crucial insights for best practice conservation.

University of New South Wales researcher Dr Kate Cornelsen studied 19 bilbies translocated to a 110 hectare predator-proof sanctuary in Dubbo, NSW, established by the Taronga Conservation Society Australia. The bilbies were released in three tranches, with Cornelsen monitoring them closely over the course of 2019 to 2021.

Cornelsen’s research is believed to be the first detailed exploration of greater bilby (Macrotis lagotis) social behaviour outside of intensively managed exhibits.

“Working with them so closely you get really fond of the species,” she says. “They’re really intelligent animals.”

Before the bilbies were released into the sanctuary, Cornelsen says she performed a range of behavioural tests, for example to see whether they were responsive to handling, to gauge whether certain traits correlated to later success after release.

The insights were made possible in part due to a new application of GPS technology for the bilby. The bilbies were tracked using a combination of tiny high frequency and GPS transmitters, which provided detailed data on their movements. The animals were also re-captured and assessed every 40 days. 

Cornelsen’s study used DNA analysis to assess any kin relationships and genetic diversity. And she developed two personality traits tests, one based on a trap test (to evaluate responses to a known threat) and a novel scent test (to evaluate their responses to novelty).

Her paper details findings about bilby characteristics, genetics, preferred habitats, social interactions, breeding success and personalities. 

She found the species had no distinct breeding season.

Bilbies share burrows quite a bit with different individuals, and those associations are non-random, Cornelsen says. 

She says males generally avoided other males, preferring to associate with the opposite sex, particularly when sharing burrows. There was also some evidence of kin-avoidance. This suggests burrows could be crucial for breeding success, she says. 

In terms of preferred habitat, female bilbies preferred sandier dune habitats – better for burrowing – and proximity to land-based insects, a high value food source. Bilby burrows can be up to two metres deep.

Bilbies with a low stress response to being handled – measured by their lower respiratory rate – were associated with stronger post-release fitness.

Bilbies did have a personality, she says, and males that responded better to handling tended to have a higher breeding success rate.

The research suggests that when translocating bilbies for conservation, it is important to consider several aspects of a species’ behaviour and ecology to make informed management decisions and increase the likelihood of success.