I am interested in knowing if there is something that can be done other than tilling. I had the same problem but I just finished tilling mine all up and re-seeding last week.
I know for burrowing critters the best fix has been pool chlorine.....if you find a rodent hole then get a tube as far down as you can get it ....pour some pool chlorine powder in there and then pour water down and then cover the hole. The chlorine gases will permanently terminate anything trying to make an apartment out of your lawn....its effective too.
