Trap, Neuter, Release (TNR) is a somewhat controversial program by which feral cats are trapped, spayed or neutered, and then released into the environment. Rather than immediately reducing numbers through removal, TNR practitioners hope to slowly reduce populations over time. 

Additional research shows, that the colony which remains is healthier and keeps other cats at bay.  Thus allowing the colony, if regularly fed, to live out its natural life without adding to the unwanted population.

In a Trap-Neuter-Return program, community cats are humanely trapped (with box traps), brought to a  veterinarian to be spayed or neutered, vaccinated, eartipped. The corner of one ear is squared off. This allows observers to quickly determine that the animal has been sterilized.