Drone-Baiting Successfully Mitigates Mouse Threat on Browse Island

Amid ongoing concern surrounding the detection of the H5N1 bird flu in Australia, a team of scientists has mitigated another predatory threat by employing drone-baiting.

Thousands of mice had been running rampant on Browse Island, 450 kilometres off the coast of Broome, since the late 1800s, preying on eggs and disturbing breeding patterns of migratory seabirds.

Browse Island, which covers 17 hectares, was once considered a haven for seabirds and crucial to the overall migratory ecosystem in WA's far north.

Department of Biodiversity, Conservation and Attractions (DBCA) Kimberley conservation coordinator Bruce Greatwich said their "world-first" drone-baiting eradication program,which specifically targeted the mice in October last year, had shown early signs of success.

Early signs of success

The drones focused on the island's infestation of the invasive south-east Asian house mouse, believed to have been introduced during the island's guano-mining days or by foreign fishers.

Six months later, DBCA scientists and conservation staff returned to assess the success of the program, using traps, motion-sensor cameras and thermal scanners.

"Island rodent eradication projects have been happening for decades, and they've largely been delivered by hand baiting on the ground or otherwise dropped from the air by helicopters," Mr Greatwich said.

He said the relatively new drone-baiting technology delivered a higher level of accuracy, compared to alternative methods. They were also much faster compared to research groups having to walk around and deliver baits in often dense scrub and soaring heat.

The impact of eradicating mice from Browse Island goes far beyond the confines of the small stretch of uninhabited land.

Migratory seabirds typically breed on offshore islands, rather than on the mainland, which is why remote islands are significant to the population's ability to thrive, according to Mr Greatwich.

"There's a very small number of offshore islands on the north-west that maintain our regional breeding seabird population, so it's really important all those islands play their role as part of the bigger picture."

Critical time for conservation

The recent detection of bird flu in Australia has sparked concern about the steps being taken to protect vulnerable species.

The H5 variant has devastated wildlife and poultry farms worldwide since it was first identified 20 years ago.

Overall, there have been five identified cases of H5 avian influenza across the country.

Mr Greatwich said the success of programs, like drone-baiting, showed the benefit of non-variable "threat removal" and "practical action".

"By doing this sort of management action, we're building the resilience in these populations of seabirds to then hopefully be able to absorb other unforeseen impacts — so, something like bird flu," Mr Greatwich said.

"Because we never know what's around the corner, something like bird flu popping up, it's something that hasn't been forecast but now is a very real threat to these species."

DBCA said formal eradication could not be declared until 12 months after the initial baiting, which will be October 2026.