By Georgie Hanafin
A Stewart Island/Rakiura ratepayer has escalated his giant rates hike to elected members of the Southland District Council, from his home in Christchurch. Photo: Stephen Jaquiery/ODT
It is a game of cat and mouse on Rakiura-Stewart Island after images of small rodents were captured during a routine surveillance operation.
Rakiura was thought to be mouse-free, but images from surveillance cameras in 2023 showed small rodents.
The Southland Regional Council had been unable to conclude if the image was of a mouse or small rat.
Council spokesperson Ali Meade said a hidden mouse population could be devastating for Rakiura's ecosystem and taonga species.
"Wētā, any of the caterpillars, any of the spiders that are living on the island would be preyed upon, eaten, their numbers reduced. That has a knock on impact in terms of pollination of native species. Any of the plant species that are producing berries or fruit that would be palatable. So the impacts of rodents on those species is direct and has major implications for the whole health of the ecosystem," she said.
Three species of rat already lived on the island, but Meade said adding mice to the mix would change the delicate ecosystem, which could be disastrous.
Mice eat insects and seeds which slowed the pollination and growth of native plants, she said.
"They compete with native birds by eating many of the same foods like seeds and invertebrates. When mice eat seeds they destroy them, whereas when birds eat fruits and seeds, the seeds usually survive through the digestive tract and are dispersed as a natural way for native trees to colonise new areas."
It was important to find any hidden population of mice on Rakiura, Meade said.
If they were successful in eradicating their natural predators, such as rats, feral cats, possums and hedgehogs, it could create the ideal environment for a mouse population to increase, she said.
The council installed traps and further video surveillance would be monitored for the next two weeks.
