The original trap-neuter-release (TNR) program was begun in 1990 Alley Cat Allies which is based out of Bethesda, MD. The founders of this group realized that when well-meaning citizens were calling the animal control officers or towns about feral cats, the only response the authorities had was to kill the cats. The Ally Cat Allies founders therefore developed educational materials and wrote step–by-step instructions on the care and protection of stray and feral cats. Their type of program has since become an accepted and proven method for effectively and humanely reducing the feral cat population.
The reason the TNR program works more than any other methods is that it is based on feral cat behavior and simple math. Abandoned, lost or feral cats tend to stay in select groups around a food source. They are protective of their food source and will limit new cats from joining their established group. If the cats in the colony are methodically trapped-neutered and released back to the colony, over time there are fewer and fewer of them that can reproduce. In addition, since they will generally continue to guard against letting new cats enter their territory, eventually there will be no adult cats left that can reproduce and continue the growth of the colony. Sometimes a new cat will be accepted into a colony, however, such a cat would simply be identified as a new member and trapped-neutered and released just as the others. The feral cat colonies are typically monitored by people who check on and feed the cats daily. Although the cats are technically wild, a feral colony with a consistent, provided food source will be less likely to be nuisance to the surrounding human population. Due to the hardships and hazards of outdoor living, the average life span of a feral cat is only about 3 years. Therefore, a properly managed colony will eventually disappear as a result of the diminished procreation.
People often ask why can't feral cats be adopted and taken in as pets rather than released back to the outdoors. Feral cats are technically wild animals and have learned to fear humans as part of their survival instinct. They are elusive and do not easily adapt, if ever, to living indoors. It is extremely difficult to keep an adult feral cat as a pet since they will be unsocialized. (Feral kittens on the other hand can be trapped at a young age, socialized and adopted out.)
Feral cats are elusive and have learned to fear humans as part of their survival instinct. Long ago mankind domesticated these animals leaving the feral cat in a compromised position. It is not capable of surviving without mankind and feral cats live a harsh life. It is only fair to these creatures that we intervene and provide assistance. The TNR programs are the best way to humanely regulate these animals so that the population does not continue to grow.