Chipmunks tunnelling in garden
Apparently it is chipmunks (not the red squirrels we had suspected) that are burrowing in the garden around our plane tree. The hostas and the ferns are not happy about it.
Are there any proven methods for keeping this problem under control? Is it a question of just keeping filling in the holes? My only significant concern is that they have dug out gravel from under a retaining wall in the garden.