(Austin, TX USA)
Feral cats serve a useful purpose and have been in the Americas for as long as 400 years
In fact, feral cats have been on the scene as long as Europeans have had contact. Most of these feral cats piggyback on human settlements, mostly because we humans create a local environment favorable to mice and rats — from storing grains like rice, wheat and such, and because of our garbage heaps.
Feral cats keep the rat and mice populations in check, and for that reason alone, we should let them breed and propagate. There was a period in human history, in Europe in the middle ages, where cats were killed and persecuted. Then came the Asian rats and the black death, with no cats to keep them in check. It could happen here.
So I say, let the feral cat populations be — they serve a useful purpose to keep the rat and mice populations in check that humans settlements to to foster.