Sure, we'll ruin it just by being human, and all that goes along with it; for millennia, that's included cats.
Any one issue wouldn't be an issue without the others... if birds were not under pressure from every conceivable angle, any one angle wouldn't be a catastrophe. The real issue is holistic, and it is us. For birds it's habitat loss, pesticide and herbicide, hunting, poisoning, trapping, mirror-solar arrays, wind turbines, cats, etc... etc... etc...
The story is the same everywhere, and the nature of the pressure is that there are too damned many of us.