One by one, the tiny turtles scuttled across the sand and into the sea.

For conservationists who have been battling to keep predators away from the critically endangered hawksbill sea turtles of Maria Langa Key in Puerto Rico, the sight was something to celebrate.

The short journey from nesting sites to the sea had previously been a gauntlet to run for the turtles, harassed in the open by a troublesome population of introduced rats on the island.

But this year, their path had been cleared thanks to a piece of Kiwi ingenuity which has proven a fearsome weapon in the battle for our own cherished native species.


The 6.1 hectare mangrove key is a major nesting site not only for the turtles, but to the brown pelican and other seabirds and lizards, all of which have suffered heavily from predation.

Users of the island, including fishers, recreational visitors and the local community, were worried the large number of rats were destroying the habitat, but did not want rodenticide toxins in the environment.

Last year, Hector Ruiz of the Guardians of Maria Langa Island project contacted Wellington company Goodnature, whose self-resetting A24 traps are deployed by the Department of Conservation in important native bird habitats around New Zealand.

After 10 of the traps were set up around the island, 24 rat carcasses were collected after the first night, and a further 80 were counted over the next few months.

Mr Ruiz had since watched the endangered turtle population began to recover.

"We are watching turtles making it to the sea without being harassed," he said.

"In the past the rats harass the eggs and the small turtles."

Goodnature director Robbie van Dam was pleased to see the homegrown technology being put to good use around the world.

"Halting biodiversity decline in Puerto Rico with traps built in Wellington shows the massive part kiwis can play in global conservation," he said.

"We achieved the ultimate rat control standard in DoC trials here in New Zealand and now our traps are achieving the same offshore."

Powered by compressed C02 canisters, the traps reset themselves after striking and can kill up to 24 rats before the canisters need replacing.

Earlier this year, Department of Conservation officials were impressed by a trial of the traps in Onepu in Te Urewera and Boundary Stream northwest of Napier, where predator numbers were reduced to zero.

Kevin O'Connor, deputy director general of DOC's Conservation Services Group, described the trials as "very promising" and a "significant step towards having a better and more effective trapping option for predator control in New Zealand".