Pileated Woodpecker Nest or Excavations in rotted tree

Pileated Woodpeckers create rectangular feeding holes. These cavities can be as much as 12 inches in length and multiple cavities can sometimes be observed on a single tree. Pileated woodpeckers also excavate nest holes. These are round, in contrast to their feeding holes. The large holes abandoned by the woodpeckers are used by other animals as nest holes, or as shelter. http://www.bear-tracker.com/pileatedwoodpecker.htm