I shoot lawn buffalo, aka ground hogs, all the time with my Ruger 10-22. They are practically an infestation on my uncle's farm. I try to hit the in the front half of the body somewhere and they never travel more than 10 feet before turning belly up and wetting themselves. I would just pick a spot not more than 50-60 yards away from the holes and set up a good rest and get to it. I have good buffalo hunting all day where I go, but I guess in other places they may only come out around dark. My suggestion would be to use a hollow point bullet. You only need to penetrate about 2 inches to get into the vitals and you want to do a TON of damage.