The stoat (Mustela erminea) was introduced into New Zealand to control introduced rabbits and hares, but is now a major threat to the native bird population. The natural range of the stoat is limited to parts of the Northern Hemisphere. Immediately before human settlement, New Zealand did not have any land-based mammals apart from bats, but Polynesian and European settlers introduced a wide variety of animals. Rarely, in Southland, the fur of stoats has been reported to turn white, being the fur known as ermine, which adorns royal robes.[1]