How can I tell?? My yard is very lumpy with hundreds of little mounds of dirt. The grass isn't great. The mounds are a bit bigger than a quarter. There are 1/4 inch holes under each one. I dug down under several and couldn't find anything. I know that I have lots of worms. I did have an ant hill - could these be hundreds of tunnels? I also have ground bees. I don't really mind the ground bees or the worms but I don't like the lumpy lawn. I'd like to look after the grass but I don't want to do a lot of work only to find I have massive ant hill. I haven't been able to see anything at most of the holes (except a few in one section are clearly ground bees).