DOC to kill 200K mice on NZ islands

DOC to kill 200K mice on NZ islands

Sixty-five tonnes of poison is about rain down on mouse-infested islands off the New Zealand coast, as conservationists try to save the local native birds and plants.

The remote Antipodes Islands sit 760 kilometres south-east of New Zealand in sub-Antarctic waters.

They're home to a range of wildlife, including 60 bird species, 150 insects, and around 200,000 mice thought to have been introduced to the islands 100 years ago in a shipwreck. That's 150 for each of the island's 2200 hectares.

A team of 13 people, including Department of Conservation (DOC) workers and helicopter pilots, have been flicking mice off their sleeping bags after setting up a base and a helicopter hanger as part of a $3.5 million eradication programme running over the winter.

Project manager Stephen Horn says the aim is to kill every single mouse on the island in one swoop.

"It is important to do it all at one time and we're here in the winter primarily because of the vulnerability of mice in the winter, there's much less food around for them so they're more likely to take the bait," he says.

"Once we get rid of them, the wildlife here, which is pretty unique and special on a global scale, is protected, and we don't have to do any more management."

Helicopters equipped with an 'under-slung' bucket and a spinner will fire bait over practically every part of the island and a radius of 80 metres in two specific operations. The stakes are high -- miss just one pregnant female, and the whole job is a failure.

The project, known as the 'Million Dollar Mouse', was initially funded through a public fundraiser organised by philanthropist Gareth Morgan in 2012. Costs have blown out with unexpected delays and changes to the plan pushing the project closer to $3.5 million dollars.  

"They gave me an estimate of how much it would cost and I said, 'right'. I'd had too much wine actually -- I said, 'right, let's do it, you've got it', and woke with a headache and wondered how the hell I was going to find the money," Mr Morgan says.

"But the biodiversity that they're trying to protect down there is really essential, because that's what makes us robust as a species, so as soon as you lose bio-diversity and have mono-cultures, then we're all vulnerable from disease."

The operation had gone well to date but the winter season was likely to create some difficult conditions for the crew.

"Everything's going good, but it's only as good as tomorrow's storm," he says.

"They have to do it in the winter because that's when the mice numbers are the lowest and also a lot of the species are at sea, so you minimise your chance of bio-kill. It's also the time of the roughest weather, hard to get on and off the weather, and hard to get the right flying conditions."

DOC's threatened species ambassador, Nicola Toki, emphasised how much damage the mice do.

"They're birds like snipe, and pipit, and particularly Antipodes Island parakeets that are only found in these islands," she says.

"In other places we do know that mice have actually been seen eating albatross chicks while they were sitting there waiting to fledge, so they're always going to be a danger. The mice eat a lot of invertebrates and a lot of seed and so they're actually destroying the integrity of that site as a lifeboat for wildlife."

The operation, which will involve two poison drops at least 14 days apart, is ready to get underway with crews simply waiting for a break in the traditionally awful winter wind and rain. It could be a long wait for the team, which is carrying five months' worth of provisions.

Mr Horn says two people have already been getting up close and personal with the subject matter.

"[One] had mice running over him in his sleeping bag over the last few nights, so he's got an incentive to make sure the operation works from a personal point of view as well," he says.

"[The other] got up in the middle of the night and unzipped his tent, and a mouse jumped inside and he was busy chasing him around the tent. He noticed there was a bit of water pooling inside -- he got a fair bit of his clothing damp in the ensuing pursuit."

With 13 people fighting 200,000 mice, that uncomfortable experience is likely to continue.