12 Apr 2012

Eradicating stoats from Resolution Island

From Our Changing World, 9:20 pm on 12 April 2012

Pete McMurtrie with a dead stoat, and a Fiordland skink

The good guys and the bad guys - Pete McMurtrie celebrates another successful stoat kill (left), while Fiordland skinks (right) are thriving now that the Resolution Island stoat population has been reduced to neglible levels (Images: A. Ballance)

The Fiordland Islands Restoration Programme is an ambitious effort by the Department of Conservation to remove introduced animals and restore native biodiversity on some of the hundreds of islands in Fiordland National Park. The programme began in 1988 with the eradication of rats from Breaksea Island, and more recently has been removing deer and stoats from the two largest islands in Fiordland, Secretary and Resolution islands. Resolution Island became the world’s first designated island sanctuary in 1891, and is New Zealand’s seventh largest island, just a bit smaller than Great Barrier Island. In the late 1800s conservationist Richard Henry moved hundreds of kakapo and kiwi from the mainland to the safety of Resolution Island – this pioneering island translocation effort, however, was doomed when predatory introduced stoats reached the island in 1900. In this Our Changing World special feature Alison Ballance joins an 8-day Department of Conservation stoat-trapping trip to remote Dusky Sound, on board the boat Southern Winds, to find out how effective 2315 traps are at eliminating stoats on a rugged forest-covered island that is nearly 21,000 hectares in size.

Trapping stoats on Resolution Island - equipment, and a trap check

It takes an egg to catch a stoat - three times a year more than 1150 eggs and 2315 pieces of salted meat are placed in kill traps around Resolution Island (images: A. Ballance)

Web-only interview - DNA and genetic analysis are providing useful insights into whether stoats being caught during the trapping programme are resident on Secretary and Resolution islands, or whether they are new immigrants that have swum across from the adjacent mainland. University of Auckland PhD student Andrew Veale is carrying out the genetic analyses, and Alison Ballance catches up with him in a genetics lab at Landcare Research in Auckland to hear about his preliminary results.

Dusky Sound on a bad weather day and on a nice sunny day

The two faces of Fiordland weather - DoC rangers brave a storm on the back deck of the Southern Winds, and a view from the top of Resolution Island the following day (images: A. Ballance)