Stoats

Introduction to New Zealand

Stoats were introduced into New Zealand during the late 19th century to control rabbits and hares, but are now a major threat to native bird populations. The introduction of stoats was opposed by scientists in New Zealand and Britain, including the New Zealand ornithologist Walter Buller. The warnings were ignored and stoats began to be introduced from Britain in the 1880s, resulting in a noticeable decline in bird populations within six years. Stoats are a serious threat to ground- and hole-nesting birds, since the latter have very few means of escaping predation. The highest rates of stoat predation occur after seasonal gluts in southern beechmast (beechnuts), which enable the reproduction of rodents on which stoats also feed, enabling stoats to increase their own numbers. For instance, the endangered South Island takahē's wild population dropped by a third between 2006 and 2007, after a stoat plague triggered by the 2005–06 mast wiped out more than half the takahē in untrapped areas.