Green Stray Cat, Varna, Bulgaria

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.