moles i'm thinking. if they are not near gardens you can get by with leaving them alone and just raking the dirt out to spread it around. they do create habitat for voles, mice, snakes, chipmunks, frogs, toads.
in more formal gardens they sure can make a mess. i do have traps for them of a few kinds. at first i was using a choker loop type which is hard to set, but they do work, now we have the type that you can just step on it to set it that looks like this:
if you are into skinning and tanning hides they have amazingly soft fur.