On one April day, a female acorn woodpecker (Melanerpes fomicivorus) was observed drilling an astounding 286 holes into the trunk of a pine tree over the course of nine hours and 27 minutes. Why? So she and her fellow woodpeckers could tuck an acorn into each and every one. The so-called "granary tree" or "nut pole" is used by the group over several years and can eventually have as many as 50,000 holes.