TNR is a program in which outdoor cats are humanely trapped, brought to a vet to be vaccinated, spayed/neutered, and finally ear tipped. The ear tipping is a universal sign that an outdoor or fetal cat has been neutered and vaccinated. After the vet visit, they are returned to their community.
In the past, feline overpopulation was dealt with by catching and killing feral or outdoor cats. Many found this to be a cruel practice, as once a feline was captured and killed another would take it’s place. The new cats breed and the whole cycle starts over again. But another solution was discovered. Trap-Neuter-Release. This was found to be a much more efficient, and cost effective, way to control the wild feline population.