Stowaway mice a problem for predator-free island

Tuesday, 8 January 2019

Wild mice have been discovered on Maud Island.

Stowaway mice have put the predator-free status of a vital wildlife sanctuary at risk.

Maud Island wildlife sanctuary in the Marlborough Sounds has been invaded by mice. The invasion puts the lives of protected species, including rare invertebrates and lizards in jeopardy.

New rangers tasked with keeping the island predator-free have revealed their first task was to tackle the tiny scourge.

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Emmanuel Oyston and Anna Star, along with Fergus, 5, and Quintin, 2, have taken up the reins for the next three years as the new Department of Conservation resident rangers in Pelorus Sound.

Oyston said they believed the mice had managed to sneak onto the 320 hectare (800 acres) island from a boat or had possibly caught a ride on floating debris.

'A chunk of our work at the moment is planning a mouse eradication from the island in June.

'Mice made their way onto the island … either through coming on a vessel or rafting on flotsam, and they pose a significant threat to some of the rare invertebrates and lizards found on the island,' he said.

Mice were found on the island in the spring of 2013, and were eradicated using baits laced with rodent poison and the island was once again declared predator-free in 2016.

Emmanuel Oyston and Anna Star, along with children Fergus and Quintin have taken up the reins as the new Department of Conservation resident rangers in Pelorus Sound.

Department of Conservation staff said the operation would involve aerial distribution of bait containing the rodent toxin brodifacoum.

This method has been used in the past to eradicate rats and mice on a number of Marlborough Sounds islands.

A DOC spokeswoman said the island was still classed as predator-free.

'We still treat the island as 'predator-free' as we still need to prevent anything else reaching the island, such as stoats, argentine ants, weeds etc.'

Star said living on the island gave the family a sense of what life on mainland New Zealand would have been like before the introduction of predators.

Brothers Quintin, 2, left, and Fergus, 5, are enjoying life on Maud Island.

'The abundant amount of tūī and kererū that carelessly and constantly dive in front of you is pretty phenomenal.

'But the island really comes into its own at night here - where cries of morepork, little penguin and the grating of tree wētā fill the night air.

'Geckos come out to feed on the ground and shrubs and you need to be pretty careful not to step on 40-year-old plus frogs or giant wētā the size of your hand,' she said.

Maud Island is home to Quintin, 2, left and Fergus, 5, who live with their ranger parents on the wildlife reserve.

'You start to get a sense of what mainland New Zealand was like before rodents, mustelids and possums were introduced in the 19th century.'

The couple were passionate about conservation, with both coming to the ranger roles from a background in predator control.

Oyston said their work on the island was similar to 'running a small 300-hectare farm in challenging terrain'.

'Instead of yielding livestock for profit, we are protecting and allowing rare native critters to populate for their persistence and ultimately for future generations and ecosystems to benefit from,' he said.

People will have the once-a-year opportunity to get up close and personal with the inhabitants of Te Pākeka/Maud Island as part of the DOC's Summer Explorer Programme.

Oysten and Star will be on hand to show visitors an array of the invertebrates, rare frog and lizard species, as well as a guided walk to the island's WWII gun emplacement.

Trips will take place on January 12, 13, 19 and 20. The trip costs $130 for adults and $65 for children (13 years and under). For bookings and information visit pelorustours.co.nz.