Cara, as I mentioned in the article, feral cats are a form of pollution spread by humans. Feral and free-ranging cats and rats are the most harmful human-caused impacts on endangered species, particularly on islands, in cities worldwide, and in Australia. In fact, feral cats are among the worst plagues humans have inflicted on wild animals. Not only that, but feral cats are the only "inadvertent" human-caused mortality that would be relatively easy to fix. Kind of hard to do without glass windows or communication towers (which kill birds), but the environment does not need feral cats.