Spot on Mr Magoo I think!
Almost definitley eaten by a small rodent, probably a Woodmouse (like Thunder and I suggested).
But not wedged into the bark by one (like thunder and you suggested).
Possible culprits - corvid (jay etc...) squirrel, nuthatch (doubt it - they DO wedge nuts in trees but 2' off the ground would seem to be too low in my opinion anyway), human.
Doug