Ignorant humans. Domestic cats have been in North America for over 400 years and their wild cousins much longer. The wildlife that should be concerned about them are rodents and small birds some of which are imports too and all of which have evolved knowing about cats. Since most of the wild cats are now gone who do you think is keeping the world from being overwhelmed by mice, rats and starlings? Would you rather use poison to protect your grain and your abandoned buildings. Maybe you don't mind having shrews and voles in your cupboards either. Cats should go on strike for a while so you can see how wrong you are about the impact of cats in your sad lives. Dopes like you killed off the cats during the "Great Plague" instead of the rats they hunted who carried the disease...