It's called Trap/Neuter/Return (T/N/R). The program in the US came from a few cat volunteers in Washington DC Who got tired of seeing perfectly healthy cats who were simply unsocialised being rounded up and killed only to have more cats move in and take their place. They formed an organization called Allet Cat Alies. http://www.aleycat.org They have put together statistics and studies that show that TNR is much more efficient and effective than catch-and-kill. Their mission is education, and helping other sites institution TNR. Stray or abandoned cats are comfortable with people and can be taken off the street and found new homes. Feral cats were never socialized to people when they were young, or they have been on the streets so long that they have reverted to the wild. They will never make good pets and would be miserable living indoors. They are live-trapped, fixed, vaccinated, and the tip of the left ear is cut off as a visible sign that this is a fixed feral. If you can get at least 70% of the colony fixed, then the die-off rate will exceed the birth rate and the population will gradually go down, meanwhile being place holders to keep more cats from moving in. It's cheaper, more effective, and more humane.
