Something in the past week has been digging shallow holes in my grass and beds. I've noticed a little digging in my compost bin, but I haven't been putting in food scraps lately because we found evidence of rats in our attic and garage (and caught a few). I don't have pets but have dogs around us. The digging seems to be happening at night. I live in suburbia, so we're surrounded by houses. Any ideas on what it could be, and how to deter it?