Posted: 13/03/2017 at 09:40
Looks like a rat hole. They are very clever and when something new is put near where they are running will avoid the new"thing" for a couple of weeks. I had to leave traps down for two or three weeks before catching anything.
My neighbours have ducks and chickens so I am always finding excavations in the dry stone walls and banks around my garden. Have given up trying to control them, I just hammer a large stone into the entrance, they are very persistent and industrious though, just dig a new hole somewhere else. The trouble is this does eventually lead to the collapse of the walls and banks as they create extensive tunnel systems. Cannot help but admire their determination