Trap Neuter and Return
"Trap-Neuter-Return is the humane and effective approach for stray and feral cats. Now in practice for decades in the US after being proven in Europe, scientific studies show that Trap-Neuter-Return improves the lives of feral cats, improves their relationships with the people who live near them, and decreases the size of colonies over time. " (Alley Cat Allies)
"Trapping cats and bringing them to HSSV to be spayed or neutered means they can no longer have kittens and unwanted behaviors such as yowling, fighting and spraying are dramatically reduced. And unlike traditional "trap and kill" practices, by returning spayed and neutered cats back to their outdoor home keeps new unspayed/unneutered cats from moving in and repopulating the neighborhood.”
(Humane Society Silicoln Valley)