Some TNR organizations claim to have trapped, neutered, and released thousands of cats over just a few years. TNR is especially popular in California and Florida, but interest is growing across the country. The founding theory behind TNR is based on perpetual management of cat colonies. There is little data to substantiate such claims. Cat colonies often serve as dumping grounds for unwanted cats and the food often attracts more cats.
Colonies often contain cats too wary to be caught.
Contrary to claims by feeders, colony cats do not keep other cats from joining a colony. Domestic cats are not strictly territorial because they do not exclude other cats from a given area. Diseases that can be transmitted to humans, such as ringworm, cat scratch fever, and toxoplasmosis, cannot be controlled in managed cat colonies. Rabies is a very real threat, and raccoons and skunks are two of the most common carriers of the disease in wildlife. Raccoons and skunks are attracted to feeding stations, as well as foxes, opossums, skunks, and rats.