Unexplained discovery of dead stoat on Stewart Island

The Department of Conservation is investigating the unexplained discovery of a dead stoat on Stewart Island.

Rakiura is known to be stoat-free with the nearest population 30km away across the Foveaux Strait.

The dead stoat was found on the Rakiura Great Walk Track earlier this month with its skull crushed, either from a trap or similar blunt force.

The department's Southern South Island Director of Operations, Aaron Fleming, said a stoat's swimming range was 2km and they were not known to stowaway on boats.

"This stoat has died from a head injury then mysteriously turned up on a busy walking track," Fleming said.

"We need to know if we are dealing with a new significant threat to Rakiura's native species, or if this stoat has been transported from elsewhere and planted deliberately.

"Both scenarios are disturbing. We are taking this seriously."

Genetic testing was underway to try to work out where the stoat had come from.

The department was asking anyone with information to come forward.

Fleming said stoats would have devastating impacts on the native wildlife if they established a population on Rakiura, threatening the efforts to create a predator-free space for kākāpō to be returned.

"In other places in New Zealand where there are stoats, kiwi chick survival can be as low as zero without sustained pest control," he said.

"Imagine the damage stoats could do on Rakiura, which is known for its tokoeka or southern brown kiwi population."

A predator free project was working to eradicate all of the island's existing pest species, which included rats, possums, feral cats and hedgehogs.

Introducing pests including stoats was illegal and penalties included up to five years imprisonment and significant fines.

rnz.co.nz