Freeze-dried Rat for Stoats

Forest and Bird, Issue 297, 1 August 2000, Page 5

Freeze-dried Rat for Stoats

Opotiki.

—Meg Collins,

| reeze-dried rats are becoming a new weapon in the armoury for killing stoats in New Zealand; says Pete Shaw, manager of Te Urewera Mainland Island Project for the Department of Conservation. As elsewhere, stoats are a major factor in the loss of native birds including kiwi in Te Urewera National Park. By analyzing the stomach contents of captured stoats, Pete Shaw discovered a high percentage of digested rats. Initially he tried to capture the stoats by placing a dead rat in each trap. Unfortunately, after one or two days the rats rotted away, so he hit upon the idea of freeze-drying them, so they would last longer. ‘Freeze drying is really only taking the moisture out of the rat. It comes back from the factory, dry and crunchy, according to Pete Shaw. "Then we wire them up to

look real, and "bingo!"; another stoat has bit the dust. The rat then lasts for up to six weeks before it gets a bit mouldy. ‘As a trial since February we set two lines of stoat traps, one with the usual plastic egg and the other with dried rats. Since then we have caught 57 stoats in a 1300 hectare block, and 50 were caught with the rats so we reckon we are on to something, he says. The mainland island project in northern Te Urewera has now been going for five years, and covers an area of 50,000 hectares. It has been identified as having the best complement of birds in natural forests in the North Island, with core-breeding areas for kokako, kaka, kiwi, kereru and bush robin. There are also some rare clumps of mistletoe. "The dawn chorus here now in spring and summer is deafening; according to Pete Shaw, ‘with

almost wall-to-wall kokako with their distinctive bell-like calls. Nationally, kiwi are not doing well, as 95 percent of the chicks are killed, half of them by stoats. In the northern Te Urewera 70 percent survive. There has been an ongoing programme to control pests,

especially possums, rats, and stoats in this project. The possum numbers are now at a very low level. As a result the young native seedlings, fruit and berries are providing the birds with more food leading to greater breeding success.