Shooting cats isn't that easy always, lots of reasons have already been mentioned although taking a cat out of the environment is a good thing for ground nesting birds like the quail mentioned. But removing cats from an area has to be done with discretion, since the public sees them as furry pets and not the envrionmental terrors that they are. I personaly will take out any feral cats while I am hunting unless told otherwise by the land owner. Whatever it is you do with the cat problem try to be discreet about it, that will benefit all of us hunters. Also if youre noticing a decrease in quail focus on the habitat as much as you do the predator situation, always think habitat first and then predators.