Illinois wildlife biologists say coyotes, known to be killers of domestic pets, might also be causing a decline in the Chicago area's fox population.
"Where there are coyotes and foxes, the coyotes kill the foxes," Bob Bluett, an Illinois state wildlife biologist, told The Chicago Tribune.
Numbers of both predators have been growing in the city and its suburbs for more than a decade.
While an abundance of food and an absence of hunters have allowed the coyotes to enjoy a breeding boom, scientists say foxes are being killed in disputes over food. Both coyotes and foxes focus on the same sources of food.
Bluett told the newspaper despite reports of coyote attacks on dogs and cats, people would see "things can get out of balance" when pests such as mice, rabbits and squirrels can multiply unchecked by the presence of predators.
A study involving coyote and fox populations is being conducted by biologists at Ohio State University and officials at the Max McGraw Wildlife Foundation in the Chicago area.
Copyright 2006 by United Press International
Explore further: Countering the caregiver placebo effect