I take your point Dave, but I imagine an owl eating a mouse, for example, might be affected. And I've seen some pretty huge rats here in the sticks! They could have enough of the stuff in 'em to make a cat seriously ill. But as leeneia says, cats are a real scourge for wildlife, and I'm very ashamed to be the owner of three exterminators. I'd never keep them from going out though. By the way, didn't I read recently of a new drug for thinning the blood instead of Warfarin?