Researchers at the Scottish Natural Heritage have concluded that the best way to protect populations of birds on the Western Isles is to kill the hedgehogs (Erinaceus europaeus) that are eating their eggs. According to this article from the New Scientist, the SNH considers the hedgehogs the primary cause of a major drop in the numbers of ground nesting birds. Some animal rights groups question the conclusions of the SNH, and think the scientists are overlooking other important factors that could be affecting bird populations, such as human disturbance. European hedgehogs, native to mainland Britain, were introduced to the Western Isles in 1974 for pest control.
(Thanks to a member of the ALIENS-L listserver for posting a link to this article)