The intentional introduction of exotic animals can generally be expected to yield unanticipated biological consequences. Single-purpose introductions frequently result in ecological catastrophe. Islands are particularly vulnerable to such assault. Arctic foxes [Alopex lagopus), released for fur farming on the Aleutian Islands, formerly devoid of land predators, have significantly altered nesting avifaunal diversity, abundance, and productivity. A program for restoring the historical distribution and abundance of critically affected bird species is described. In a long-term study, biological control methods are proposed to test the hypothesis that introduced sterile red foxes [Vulpes fulva), apparently, a competitively superior species, will markedly reduce or extirpate resident Arctic foxes
