Well, I'm not really a fan of cats. We have one because my wife and kids wanted one, but they can certainly do a job on rodents. Our cat only kills the occasional vole, shrew, or young rabbit, but I think the mere fact that she's around makes small mammals less inclined to take up residence in my yard. Unfortunately, it has a similar effect on birds. I do appreciate the fact that she likes to hang out in my cherry trees, though. She's not there all the time, but the birds don't seem willing to take the chance that she might be in the tree. It's nice being able to pick cherries without the robins having pecked holes in half of them.