I mark the burrows with a short flag. I put 2 small chunks of rat poison at the entrance. After the poison disappears, I keep baiting it until it doesn’t disappear. When it does not disappear, I fill the hole with rocks or dirt. If hole is dug out again, I start baiting again. Don’t do it if you have pets. Use traps or a bait station. (Neither has worked well for me, but this technique has.)