Rodent Entryways

This image is looking up below a deck at a corner in the foundation. Mice expanded an existing seam where the cut wood and concrete foundation was not flush. The grease (sebum) marks are from the hair (fur) of the mice passing through repeatedly. The ground below is littered with eaten acorns. Mirrors are essential for finding rodent entryways and performing rodent exclusion because you have to look up.