One theory is that coyotes displace foxes, which are better at reducing disease-carrying mice populations: http://www.caryinstitute.org/newsroom/fox-and-coyote-

One theory is that coyotes displace foxes, which are better at reducing disease-carrying mice populations: http://www.caryinstitute.org/newsroom/fox-and-coyote-and-ticks-oh-my http://www.caryinstitute.org/newsroom/fox-and-coyote-and-tic...