ants

They can be difficult to be rid of, but simply keep disturbing areas where you feel their nests are. Ants also don't like rich soil so also add lots of rotted manure - or even fresh manure depending on where they are in the tunnel, as you disturb them. Eventually they'll totally move on but it'll be persistence until then. At the same time, put out little containers with the special queen ant killer bait which the workers will take to her. Be sure your kids understand to leave it alone. It won't hurt them but if they spill it, your efforts are wasted.