For those of you who have not been following along from the beginning of these photographs, the small white birch that the black bear is sniffing is what is known as a marking tree or a bear tree. Although a bear may choose any tree, or even a utility pole, marking trees are most often birch or ash trees that stand by themselves near a well traveled bear trail. Bears also prefer trees that lean to one side or another, or which have a crook, as this one does.