By Ryan Anderson of 
On 6 April 2023, rat prints were found on pest-free Rotoroa Island, in the Hauraki Gulf. Photo: Facebook / Rotoroa Island
Rat prints have been found on Rotoroa, in the Hauraki Gulf, which has been pest-free since 2013 - but the island is now in danger of losing that status.
The prints were found on an ink pad trap, which sees pests walk over an inky surface and then track prints onto a white slab, on Thursday morning.
Conservationists rid the island of all pests in 2013, but now they have six weeks to find the rat, otherwise it will lose that status, according to assistant island manager Milly Lucas.
The team believe that only one rat has made it onto the island and that it came off a boat anchored in Home Bay on Wednesday, she said.
Now the workers will have to check all 300 traps on Rotoroa every 48 hours, Lucas said, and refresh the lures with rat-friendly treats including peanut butter.
"We haven't had an incursion in the past two years, which has been very lucky.
"With the last of the good weather before everyone heads back into winter, it was possibly transferred by a visitor."
Lucas asked people coming to the island via boat check to make sure they were not bringing any unwanted visitors with them.
She suggested chucking a bait box on the boat too, to further keep down the chances of rats being onboard.
Rotoroa is a private island that takes just over an hour to get to by ferry from downtown Auckland.
The island is a sanctuary to some of New Zealand's most well-known birds, including kiwi, takahē, kererū and kākā.
- This story was originally published on Stuff.
