KEY POINTS:
A mouse has sparked a full-scale search and destroy operation on Mokoia Island.
The hunt, involving 15 Department of Conservation staff and three volunteers, was launched when mouse prints were found in a tracking tunnel on the island which is home to endangered species and kept predator-free. The mouse was trapped and killed.
Department of Conservation biodiversity ranger Rebecca Lander believes the unwanted intruder arrived on the island within the last two months, when the tracking tunnels were last checked.
It's not known exactly how the mouse got to the island.
"There has been a lot of activity on the island during the past two months which may have been the cause of this episode."
Mice on Mokoia Island could ruin its predator-free image.
They are known to prey on the young chicks of small birds like fantails and tomtits and can damage forests by feeding on seeds and berries.
The Lake Rotorua island is home to endangered species including kiwi, saddleback, North Island robin, kokako and weka.
The mouse was male but had been sent to Hamilton for further testing.
"If the mouse [had] turned out to be a pregnant female then it was entirely possible that an outbreak could have occurred," she said.
The island will be monitored once a week for the next three weeks and then once a month for the next six months to make sure no other mice have made it to the island.
"While we are pleased with the relative speed at which we were able to catch the mouse, this serves as a stern reminder for constant vigilance," Ms Lander said.
Mokoia Island has been pest-free since 2001 when the last mouse eradication operation took place.
- NZPA
