How squirrels and mice break into hazel nuts

Here's a picture from the excellent Reforesting Scotland Gathering at Tighnabruaich. The site visit included a visit to Dun Beag Wood, where we found these shells. In Argyll you still find red squirrels in their original west coast home, broadleaf woodlands. Hazel nuts are an important part of their diets, but mice also eat them. In this shot, the uppermost hazel has been nibbled by a mouse, whereas the squirrel will always crack the nut in half, as seen in the lower example.