Skies above remote parts of the nation’s back country will host new technology designed to drop baits in the path of rats, stoats and possums

Poison-laden drones to patrol New Zealand wilderness on the hunt for invasive pests

Poison-laden drones to patrol New Zealand wilderness on the hunt for invasive pests

A large rat scampers across a shady forest floor in search of its latest meal of Kiwi chicks, one of New Zealand’s endangered native birds. But the rodent is in the sights of another predator – a mammoth drone carrying hundreds of kilograms of deadly poison.

This scene could soon be playing out across New Zealand’s most rugged wilderness as the Department of Conservation (DoC) considers a new high-tech strategy to halt the country’s biodiversity crisis.

A drone, which is seven metres long and looks like a mini-helicopter, is being developed to wipe out pests in areas that humans simply can’t access due to steep cliffs, deep ravines and impenetrable vegetation.

Conservation rangers usually hike into remote spots to lay bait stations and traps to kill stoats, rats and possums; invasive species the government has vowed to eradicate from the whole country by 2050.

For hard to reach parts of the wilderness, manned helicopters have been extensively used by DoC, but the department is now investigating cheaper and more environmentally friendly alternatives in an increasingly climate-aware age.

By the hour, drones are two-thirds cheaper than helicopters, and emit 85% less carbon, drone manufacturers say – a priority for a left-leaning government that has committed to being carbon neutral by 2050.

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Drones are more precise than helicopters, and are able to drop their bait loads within centimetres of the target, an important consideration when accidental poisonings of endangered native species are still occurring.

“Restoring nature so indigenous species can thrive requires new tools and technologies,” minister of conservation Eugenie Sage said. “Drones have the potential to be a game-changer.”

Brent Beaven, head of the Predator Free 2050 programme at DoC, said more than 1 million hectares of land was being targeted for pest eradication “so there’s plenty of New Zealand” for the drones to deal with.

“We are in a changing world, we can use helicopters for a lot of stuff, but our carbon footprint needs to track towards zero, we need to be looking at other options,” Beaven said. “My dream is that one day we’ll have artificial intelligence devices that will detect the presence of a pest somewhere that will automatically link to a messaging service that will send a drone out – wouldn’t that be great?”

Beaven said after three years of exterminating pests on 117 offshore islands the next phase of the project was “science”.

A sum of NZ$790,000 (£390,000) has been awarded to Kiwi startup Environment & Conservation Technologies (ECT) to engineer drone technology designed to withstand the unique challenges of the New Zealand bush, which include harsh sub-alpine environments and violent, unpredictable weather.

ECT has undertaken similar pest eradication programmes using drones in the Pacific and the Galapagos islands.

In the Galapagos, an infestation of black and brown rats was threatening the survival of the vulnerable, ground-dwelling bird population, and two drones were deployed by ECT to drop 1.5 tonnes of bait over 184 hectares in two days.

The South American regional director of Island Conservation, Karl Campbell, who worked alongside ECT said drones saved the conservation group hundreds of thousands of dollars, and were far quicker and less invasive than traditional pest eradication measures. Helicopters were previously used.

“The use of drones is more precise; it also increases feasibility, and reduces eradication costs of invasive rodents in small and mid-size islands worldwide,” Campbell said.

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The successful eradication of the rat invasion on the Galapagos is thought to be a world first.

Using knowledge gained in the Galapagos project, Sam Vye of ECT said the potential for drones in the conservation arena was “exciting”; though he ruled out weaponising the machines for armed pest extermination from the sky.

“New Zealand’s environment has extreme terrain and vegetation type and can be extremely dangerous for people on the ground to lay bait stations,” Vye said. “Using a drone we can actually fly in slightly more dangerous conditions than a manned helicopter, including to remote islands which are expensive for helicopters to get to. Compared to a manned helicopter, it also comes down to the precision and the placement of baits.”

The drone being developed for use in the New Zealand back country will be able to carry up to 170kg of bait. It requires only a drone pilot on the ground and an office worker to control it.

So far the government has totally eradicated introduced pests from 117 offshore islands, and is now focusing its attention on the mainland.

The drone trial will run over the next two years and involve three phased stages of testing.