Effects of Free-Ranging Cats on Wildlife: A Progress Report

We have embarked upon a three-year study to determine the density and distribution of free-ranging cats (Felis catus) and their effects on prey populations in rural Wisconsin. The effects of predation by free-ranging cats on wildlife populations are potentially great and have not been adequately accounted for in wildlife management programs. In rural Illinois there was an average of 5.6 free ranging cats per farm (Warner 1985). If densities elsewhere are similar, then a state such as Wisconsin, with over 200,000 active and retired farms, could have over 1 million free-ranging cats on farms. In other studies (Bradt 1949, George 1974), individual free-ranging cats have been found to capture 100 - 1000 prey per year. This could mean that hundreds of millions of prey are killed annually by cats in Wisconsin alone. We define free-ranging cats as tame, semi-tame, and feral domestic cats that are not restrained in their movements