Trap-Neuter-Vaccinate-Return (TNVR) is the only proven and humane method of managing communityl cat colonies, and is endorsed by leading animal welfare organizations such as the Humane Society of the United States (HSUS) and the American Society for the Prevention of Cruelty to Animals (ASPCA).
Community Cats are humanely trapped, spayed or neutered, vaccinated, ear-tipped (the universal symbol of a sterilized feral cat), and returned to their outdoor homes, where they are monitored by caretakers. Research has shown that, when correctly implemented, TNR stabilizes and reduces feral cat populations, eliminates undesirable behaviors associated with mating, and is more effective and cost-efficient than lethal control.
(http://www.feralcat.com/)
