One of the many definitions of the word hole is ‘an animal’s burrow’, and some of hole’s many synonyms are cavity, chamber, cave, cleft, cranny, den, lair, nest, shelter, and tunnel. These photos show a few such places, possibly but not definitely created and occupied by Great spotted woodpeckers, rabbits, voles and/or shrews, bees, and beetles. What amazes me is how perfectly engineered so many of them are.