Mouse hole project

Yesterday I spotted what looks like a well used set of holes at the base of a tree.
There seems to be a lot of scree around the bottom of the hole and what looks like a path from the holes around the tree going left to right.

I'll be back with sliced apple etc. to see if i can get anything to come out.

I've been looking at wheat fields to try and see a mouse, yesterday one ran across the path in front of me.