Red Fox in Colorado
Some red foxes in the United States originated in Europe, but most are indigenous to the U.S. and Canada (Statham, Sacks, Aubry, Perrine, and Wisely, 2012).
Work Cited
The origin of recently established red fox populations in the United States: translocations or natural range expansions? By Mark J. Statham (Kansas State University), Benjamin N. Sacks (University of California, Davis), Keith B. Aubry (U.S. Dept. of Agriculture Forest Service), John D. Perrine (California Polytechnic State University), and Samantha M. Wisely (Kansas State University). Journal of Mammalogy, Feb 2012, Vol. 93, Issue 1, p52-65.
Red Foxes Origin 