Australian island sets stage for world-first mice eradication attempt using drones

Australian Geographic – By Natsumi Penberthy • 6 May 2026

Browse Island, a tiny bump in the sea off the coast of Western Australia, has become the focus of a world-first attempt to support seabirds by eradicating its mice using drones.

Rats and mice have been hitching rides on boats for centuries – but on islands often devoid of endemic mammals, they are extinction engines, disrupting whole ecosystems.

Today, islands account for 5 per cent of the world’s landmass and a wildly disproportionate 61 per cent of modern species extinction.

Fortunately, for the seabirds of Browse Island – a small remote 17-hectare nature reserve in the Timor Sea managed by the WA Parks and Wildlife Service – a small drone baiting company from New Zealand has been involved in a series of island-rodent eradication successes.

Browse Island’s mice problem

A mouse scampering across the nest of a breeding brown booby (Sula leucogaster) is indicative of the problem that has faced Browse Island’s avian visitors since the late 1800s.

In fact, seabirds, harassed and at risk of losing eggs, have only just begun to breed on the tiny island again after being driven away by colonial guano miners and the arrival of feral cats and the Southeast Asian house mouse (Mus musculus castaneus) with them.

The cats and miners have long since disappeared, but recent camera-trap evidence revealed a very active mouse population, says Dr Donal Smith, a researcher at Melbourne’s Monash University. “Every single image and video had mice running around in it, often in and around nesting birds,” he says.

These mice not only predate eggs but also undermine clutches. “The thermal regulation of the egg is a critical component of its development… and eventually the bird deciding not to sit there amongst the mice anymore [could] mean that egg will fail,” Donal says.

Browse Island, located 450km north of Broome, is just one of several potential stopovers along bird migratory routes that stretch as far as the Arctic tundra in northern Russia. The good news is that the broader region has seen an increase in seabird numbers across the last 20–30 years.

While these birds spend most of their time flying over open ocean, they have to come to land to breed, explains Bruce Greatwich from Western Australia’s Parks and Wildlife Service. “And in the northwest, there’s so few of these islands that every single one is extremely important [to breeding populations].”

“Ideally what you want is three, four, five islands [in the area] that are all supporting thousands of seabirds,” says Professor Rohan Clarke, who is part of the Monash team involved in the project.

“And so, if a particular threat hits one of those islands, then…there’s other islands in the system that are doing the job.”

The observed return of breeding seabirds on Browse Island in 2018 is likely the result of a slow recovery and the increase in regional bird numbers, Rohan says, but the risk is that “birds may return to breed but repeatedly fail due to predation pressure [from mice]”.

World-first mouse trap

After a two-day boat ride in October 2025, custom drones built by New Zealand-based Envico Technologies arrived on Browse Island and precisely dropped 700kg of rodent bait pellets across the entire island.

It’s the world’s first attempt to completely eradicate an island’s mice using drones. While there have been more than 700 rodent removal projects on islands in the past 50 years, these often required time-intensive groundwork and the expensive, logistically difficult use of helicopters.

“You can send a drone out to cover an entire island in the space of a morning,” Donal says. “It would take a team of, say, six people maybe three days to cover the equivalent ground.”

The Browse Island project is largely a collaboration between researchers from Monash, WA’s Parks and Wildlife Service and industry partners. But the use of drones by Envico has already proved effective on island rats the world over, from the Galápagos in Ecuador to Palau in Micronesia.

These projects have often been done in partnership with United States-based non-profit Island Conservation, attracting support from famous names including movie star Leonardo DiCaprio.

“We’ve eradicated rodents from 25 islands around the world,” says Mike Jensen, a drone pilot and operations manager at Envico, a company founded in an Auckland garage in 2018. “This is our seventh project to date and on all our projects we’ve had 100 per cent success.”

Rats are often the focus, Rohan says, because there are far fewer islands with mice as the sole invasive vertebrate – but Browse Island was an ideal candidate due to its small size and isolation, which makes the risk of reinvasion very low.

Antipodean expertise in rodent recovery

Australia has benefited from New Zealand’s long-time leadership in island rodent eradication, including developing effective rodenticides and aerial delivery techniques. New Zealand accounted for almost half of all islands treated with rodent bait dropped from the air between 1951 and 2019, followed by Australia, Ecuador, Japan and the Seychelles.

But drones can bring down costs and increase baiting precision, so the lessons learned, including on Browse, are likely to have an increasingly global impact. As drones become more capable and affordable, rodent eradication is opening to countries that haven’t had access to helicopters or specialist teams.

Heavy‑lift agricultural drones, for instance, have recently reached consumer markets. Increasing automation will also facilitate broader use, although eradication-specific software is now critical.

On Browse Island, researchers will continue monitoring for signs of surviving mice before calling the operation a success. “Typically, it’s 12 to 24 months,” Rohan says, even as plans are forming for drone‑based rat eradication on nearby islands.