Introduction and range expansion of nonnative red foxes (Vulpes vulpes) inCalifornia

Predation on endangered species by nonnative red foxes (Vulpes vulpes) and the resulting controversy over red fox control efforts in California prompt ed our investigation of the introduction and range expansion of the red fox in California. Since the late-1800s, nonnative red foxes have been introdu ced into California by escaping from fur farms and fox hunters, through int entional releases by pet owners and fur-farm owners and translocations of p reviously introduced foxes. From 1990-1993 we conducted telephone interview s of wildlife professionals to obtain observations of nonnative red foxes o utside the historical range of the native Sierra Nel ada red fox (V. v. nec ator). Nonnative red foxes now occur throughout lowland areas of California including the Sacramento and San Joaquin valleys, San Francisco Bay-Delta area, the southern California Coast Range and Coastal Plain and most major urban areas. Their range expansion over the last 100 y was the result of po pulation growth from numerous points of introduction and exhibited by the e xponential growth typical of invading species. Fox predation on endangered species and opposition to red fox management have been the: two largest man agement issues associated with this range expansion.