My wife and I visited a friend near Oulu, Wisconsin last weekend, and when we toured his sugar bush, we saw this maple tree a pileated woodpecker was working on.
Pileated woodpeckers are common in the Driftless, and I hear them frequently. They have a loud, distinct and wild sounding call. They have a dipping flight pattern, and their large size and bold colors make the it thrilling to see them in flight! Their primary food source is ants, and the sound of a pileated excavating a tree sometimes attracts other insect eating birds. The bird that made this pile of chips was feeding, not creating a nest. The nest cavities pileated woodpeckers create provide other woodland animals with a place to live.
Pileated woodpeckers are a thrill to see and observe, and large dead and dieing trees provide the habitat for the ants the woodpeckers eat and a place for them to build nests. The opportunity to see these beautiful birds is another great reason to leave dead trees in your forest. The Cornell Lab of Ornithology has a webpage with good pictures, videos and sound recordings of pileated woodpeckers if you want to learn more.