Allow me to contribute another experience. At various times, I've lived alongside twelve different pet cats, owned by family members who were also avid birdwatc

Allow me to contribute another experience. At various times, I've lived alongside twelve different pet cats, owned by family members who were also avid birdwatchers; usually, the garden would be crowded with birds at the feeders. In terms of individuals among the cats, I guess about half have tried to stalk and catch the birds, and of those probably about half were effective. But in terms of impact, that seemingly small quarter punched above their weight to be a total menace. Carcasses of the birds and other animals (even rabbits!) would keep showing up until they were stopped with a bell collar. If left to their own devices, I don't have trouble imagining they'd put a huge dent in the local ecosystem.