This nuthatch was busily excavating a hole in an old snag (standing dead tree). Every so often it would stick its head out and shake to distribute the wood chips, as in this photo. It was hard work - I could hear much tapping inside the snag, making the nest hole just the right size. Standing dead trees are used by many species of birds for nesting, from owls down to little birds like this, and including everyone's favourite, the black-capped chickadee! A good reason for preserving snags.