Feral Cat's are just that, FERAL. ANYTHING feral is not good to native environments. Here in S. Texas the Feral Hogs are destroying land everywhere and people cant shoot enough of them to make a dent because ranchers/landowners see them as a money crop by charging folks to shoot them. Non-natives in any form are bad thing. Look at Grass Carp, Zebra Muscles, Asian "Jumping" Carp, et al. They are all "feral" and do LOTS of damage to native species. Feral cats are no different other than being cute and fuzzy. Make no mistake however, they are cute and fuzzy killers as far as native birds are concerned. This is why I have a BIG problem with catch, neuter and release BS. Once you release them back into the wild, the lack of juevos does nothing to stop them from killing native animals. I do allot of wildlife photography and have bird feeders in my yard for that purpose. I can't count the number of times I've found feral krats lying in wait for some "bird food" many times, it's just practice for killing and they don't even eat them. Fortunately, Air Arms of England has provided me with method of protecting native species in the form of a .22 TX200. I take ZERO pleasure in doing it but it's a measure that must be taken. If you have any doubt as to the impact that feral Krats can make look up the feral cat problem they have in Australia. Ferals have brought many native species there to near extinction. The cat protection thing is based on pure emotion because they're cute and fuzzy. No one bats an eye when someone kills a snake or spider but they're not cute and fuzzy to most folks (I tend to disagree).