And as a result they are quite overpopulated. It isn't "a nature" to have so many cats endangering the birds. It is humans not understanding the scale aspect of their decisions.
Which animal is the most over populated in the world; destroying the environment with global warning; building new housing and roads; building factories, which dump their waste products in the air and water systems, using up the world's finite resources, because we want new clothes/technology/decor in our houses, not because we need it; but because its the latest fashion....Its not cats!
The best bird nesting site in our county (green belt) had a school built on it, because agricultural land is the cheapest. Ditto, we have one of the rarest habitats in the world, nearby and a large company wants to build hundreds of houses on it, all for profit.
IMO, posters are using cats as scapegoats because its easier, than telling people, we should change our lifestyle, reduce our populations and live a sustainable way. Its humans that cause the most destruction of animals' homes, leaving them with nowhere to live. Why have bee and hedgehog populations crashed in the last few decades - its not because of predation by cats? Go to Africa and consider how all the big mammals have declined - and domestic cats are an irrelevance there.