Dunnart detections are 2-3 times higher inside vs outside the feral predator-free area

Australian Wildlife Conservancy (AWC), Media Release, 15 December 2022

Conservationists are feeling hopeful for the future of the endangered Kangaroo Island Dunnart (KI Dunnart) for the first time since the 2019/20 Black Summer fires. The newfound optimism comes after a large increase in detections of the species within the feral predator-free Western River Refuge (WRR).

Three years ago, in December 2019, Kangaroo Island in South Australia was severely impacted by bushfires that burnt almost 49% of the island. Australian Wildlife Conservancy (AWC), along with Kangaroo Island Land for Wildlife (KI LfW) and local landholders (the Doube family), acted with urgency to construct an 8.8km long feral predator-free fence in the Western River area to protect some of Australia’s most endangered mammals – including the small carnivorous KI Dunnart – from feral cats that utilise fire scar for easy predation.

Within the safe-haven, AWC and KI LfW have utilised camera traps to monitor the KI Dunnart population – which has persisted in unburnt patches of vegetation but remained low with small increases over the years. This year, however, there was a spike in dunnart camera activity, particularly during the month of August when there was a six-fold increase in detections – the highest rate in three years, since after the bushfires, when the dunnarts were concentrated in the small unburnt patch.

Thrilled by the results, Pat Hodgens, AWC contract Wildlife Ecologist, said the spike in detections is likely due to a breeding boom and in turn, a population increase.

“Western River Refuge is going better than we could have ever imagined,” said Pat. “We had a total of 143 dunnarts detections during the mid-year quarter (June, July and August) and 83 alone in the month of August – this is huge.”

Pat continued, saying that dunnarts have now been detected on every single monitoring site within WRR, indicating that their population is growing and confidently dispersing around the safe-haven.

“When we started monitoring the dunnarts after the bushfires, their movements were restricted to mostly unburnt patches within the WRR,” explained Pat Hodgens. “What we’ve seen now is an expansion across the entire refuge. They are moving around a lot more and that’s one of the biggest measures of success – that we’re seeing them across the entire refuge and that’s fantastic.”

Meanwhile, life outside the feral predator-free fence isn’t as easy for the dunnarts. Cameras detected 2-3 times more individuals inside the fence compared to outside. Pat said that this suggests that while there was a similar breeding boom beyond the refuge, predation by feral predators is still likely to be suppressing the population.

“Even though we carry out intensive feral cat control outside WRR, there is still pressure where cats are trying to find a weak point in the fence or they are preying upon dunnarts that move in and out of the refuge,” he explained. “More research is needed on the impact of the fence.”

Forty-two feral cats were removed from outside the fenced area last year, followed by another 22 this year. Capture rates vary depending on various factors including mice, prey population booms and seasonal conditions.

In October this year, four cats were captured in a single week, including a 6.3kg male, the heaviest cat captured near the site, and another male that was previously photographed strolling past a camera trap with a dunnart gripped in its jaw.

“We use three main methods to remove feral cats – cage traps with chicken as bait, felixers, and soft jaw foot traps,” Pat explained. “We know one method won’t work to attract all, and that’s evident in the image of the cat with the dunnart in its mouth – it’s walking straight past an open cage trap and had no interest in the juicy chicken.”

“Fortunately, the cat was drawn to one of our soft jaw foot traps covered in female urine. We were able to identify it by matching markings on the cat’s foreleg and remove the individual, preventing it from killing any more dunnarts.”

AWC and KI LfW received funding from WIRES to assist in the construction of the Western River Refuge feral predator-free fence. For more information on Western River Refuge and the work to protect the critically endangered KI Dunnart, click here.