The even darker side of the eastern gray squirrel (Sciurus carolinensis): a review of global introductions, invasion biology, and pest management strategies

The eastern gray squirrel, Sciurus carolinensis, is one of the world’s most recognized sciurids and a highly successful human commensal. Historically restricted to eastern North America, gray squirrel populations are now established in Italy, U.K., South Africa, and Australia, and squirrels continue to expand their geographic range globally. Successful introductions of S. carolinensis often result in significant negative impacts on native ecosystem integrity. As a result, countries have devised and implemented unique pest management strategies to reduce or eradicate S. carolinensis populations, but with differing levels of success. We review accounts of historical global introductions of S. carolinensis, discuss its invasive biology and impacts in non-native habitats, and recommend specific management strategies that should successfully curtail establishment of this species in non-native habitats