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Sustainable Ecosystems: Free-Ranging Cats and Their Effect on Wildlife Populations
Feral and domestic cats are estimated to kill billions of small mammals and birds each year. In certain areas of the world, it is not uncommon for either feral or domestic cats to have high population densities, creating concern regarding their level of hunting. Interest centers on free-ranging cats, as they roam freely and receive care and food from humans. Arguments abound regarding the presence of cats in the habitats of native small mammals and birds, and whether or not local ecosystems can sustain this predator-prey relationship. Studies have attempted to determine the effects of cats on local wildlife populations using various methods. Some research has focused on determining the home range of free-ranging cats using either radio telemetry techniques or the Global Positioning System (GPS). Because home-range size differs for each cat, we can estimate the size of an area where potential damage on local wildlife might occur. Another technique used to determine the effects of cats on wildlife includes evaluating feline scat for prey items. This is a valuable tool, as prey teeth can usually be used to identify the genus, and sometimes species of the prey. Unfortunately, it is impossible to accomplish complete collections of all scat from each cat, as they usually eliminate in multiple latrine areas within their home range. Incomplete scat collections increase the difficulty of estimating the true kill rate of prey by free-ranging cats. However, scat analysis has allowed us to determine that cats receiving cat food from humans continue to hunt and at least partially consume prey. Furthermore, the prey species identified in the scat often represent native species killed and consumed by the cats. Lastly, live animal trapping is another technique that may be used to estimate the population of small mammals in an area where cats are known to reside and hunt. Along with determination of home-range size and feline scat analyses, trapping provides another tool to help estimate the effect of free-ranging cats on native wildlife populations. Free-ranging cats certainly have the potential to roam and hunt in very large areas inhabited by native small mammals and birds. It remains questionable as to whether or not local ecosystems can sustain hunting by free-ranging cats.
Keywords: Cats, wildlife, hunting