We have so many little mounds of dirt you can hardly find the yard. I understand that although we have many mole hills, we likely do not have many moles (1 or 2 moles per 1-1/2 acres is normal). When we had a large dog in our yard, we did not see so many hills. Unfortunately, we no longer have a large dog and the hills have at least quadrupled. Is there any way of minimizing this problem that will not cost a fortune?