Trap-Neuter-Return, also referred to as TNR, is the only proven humane and effective method for managing feral cat colonies. The standard technique is to trap all feral cats in a colony, neuter them, and return them to their territory. Additionally, cats are often inoculated for rabies and ear-tipped for future identification as a neutered cat. Any kittens and human-friendly adults are socialized and adopted out to good homes.
There are many advantages to TNR. It stabilizes the growth of the colony by preventing new litters. The yowling and fighting often associated with feral cats is reduced, along with the odor of unneutered males marking their territory. A group of feral cats returned to its area also prevents new unneutered cats from moving in and taking over, once again starting the cycle of overpopulation and nuisance behavior.
Another major advantage to TNR is that, once implemented in a large enough area, it can reduce the influx of cats and kittens into local rescue shelters. In turn there are lower kill-rates and the cats already in shelters have a higher chance of adoption.
TNR isn’t just the best option for controlling feral cat populations, it is the only one that works. Doing nothing contributed to the current overpopulation problem. Rescuing feral cats and trying to provide good homes for them is impracticable, there are far too many and adult cats raised in the wild usually have no interest in living with humans. The traditional techniques by animal control of trapping and disposing of these cats is a lesson in futility. If any are left behind they quickly repopulate, and if none are left behind new unneutered cats will take over and begin the cycle anew. In fact, because of this, more animal control agencies than ever are willing to try TNR.