Rat Removers Place Tons of Poison to Protect Rare Birds

INVERCARGILL, New Zealand, June 7, 2001 (ENS) - Remote Campbell Island in the New Zealand sub-Antarctic is to be the focus of one of the world's most ambitious attempts at rat eradication for wildlife protection - with no guarantee of success.

Tackling a severe, longstanding infestation of large Norwegian brown rats, the $NZ 2.6 million ($US1 million) program will use helicopters to roll at least 80 tons of poison laced bait progressively across the 11,300 hectare (44 square mile) island.


New Zealand's Campbell Island is a UNESCO World Heritage Site (Photo by D. Mail courtesy UNESCO)
The aim of the operation is to entirely remove rats from Campbell Island, enabling the return of local native birds which only survive now on offshore islets, and other local wildlife.

A spokesman for the New Zealand Department of Conservation (DOCs), Tom O'Connor, described the project as "cutting edge stuff." He said DOCs does not know of any bigger operation in the world. But he also cautioned, "The scale of it, the remoteness, weather, all mean success is not guaranteed."

Rats are believed to have made their way to Campbell Island, 700 kilometers (378 nautical miles) south of New Zealand, soon after it was discovered in 1810, aboard one of the many ships that sailed to exploit fur seals there.


New Zealandís rarest duck, the Campbell Island teal (Photo courtesy Mount Bruce National Wildlife Center, New Zealand)
Along with cats, they are blamed for the extinction on the main island of at least three land bird species - snipe, pipet and flightless teal duck. These now survive either on other islets nearby, or in the case of the teal, in a captive breeding program.

Many small ground nesting seabirds, such as storm petrels, diving petrels and prions are also thought to have been prevented from using Campbell island. And the rats are blamed for changes to vegetation and invertebrate fauna, wiping out many larger insects.

New Zealand's wildlife recovery specialists have for more than a decade succeeded in restoring precarious populations of native species to the country's offshore islands after dealing with pests. Rats were first eradicated from tiny 170 hectare (420 acre) Breaksea Island in the South Island's Fiordland, and the Department of Conservation now claims success at removing them from 20 islands.

With cats having disappeared from Campbell Island and livestock now removed, rats are the sole remaining introduced animal.

For this attempt, preparations have been under way for months. They were snarled a fortnight ago when a truck carrying 18 tonnes of poison-laced bait destined for Campbell Island crashed into the sea near Kaikoura, an international marine mammal eco-tourism destination north of Christchurch.

Despite fears for the wildlife, the only confirmed damage so far appears to be in the appearance of the poison in some local mussels, according to Environment Canterbury, the district monitoring authority.

Operations are on track for this time period because June and July are the mid-winter months on Campbell Island when albatross and other seabirds are absent, rats' food sources are lowest and females are yet to begin nesting.

Later this month four helicopters will island-hop there. A team of 18 people plans to start at one end, and "roll out" the bait progressively across Campbell. They will use techniques such as a 50 percent overlap of previously baited ground to ensure there are no gaps.

In fine weather the operation could take seven days to complete. But because of the severe winter conditions that are predicted including gales and snow, three months have been allowed.

{Published in cooperation with The Antarctican}