Green Stray Cat, Varna, Bulgaria

• Control and management
Trap-Neuter-Return (TNR) involves trapping feral cats, spaying or neutering them, and then returning them to the place where there were originally trapped; where ongoing care is provided by caregivers. When neutered, the cats receive vaccinations against rabies, and attention to other medical needs, such as dental care and flea treatments. TNR programs are prevalent in several countries, including England, Italy, Canada and the United States, supported by many local and state governments. Various long-term studies have shown that TNR is effective in stopping reproduction and reducing the population over time. TNR results in fewer complaints, as nuisance behaviors diminish following neutering, and the quality of life of the cats is improved. The practice is reported to save money, and garner more public support and better morale, than efforts that involve killing cats.
The International Companion Animal Management Coalition advocates for TNR as a humane method of controlling feral cat populations. In the U.S., the practice is endorsed by the Humane Society of the United States and the National Animal Control Association. While the United States Department of Defense does not formally advocate TNR, it provides information to military installations on how to implement TNR programs; with the main message that population control programs must be humane.
The multiple, managed, feral colonies at the Colosseum in Rome exceed 250 cats. Other notable colonies include the Canadian Parliamentary Cats, and the cats of Jerusalem.