drumming http://birds.cornell.edu/wp_about/biology.html Woodpecker Biology Cornell Lab of Ornithology in a hopping fashion http://www.birds.cornell.edu/wp_about/biology.html Cornell Lab of Ornithology: Woodpecker Biology and Behavior http://www.birds.cornell.edu/wp_about/biology.html http://www.birds.cornell.edu/wp_about/biology.html http://birds.cornell.edu/wp_about/biology.html http://www.birds.cornell.edu/wp_about/biology.html http://www.birds.cornell.edu/wp_about/biology.html http://www.birds.cornell.edu/wp_about/biology.html http://www.birds.cornell.edu/wp_about/biology.html birds.cornell.edu http://www.birds.cornell.edu/wp_about/biology.html drumming http://www.birds.cornell.edu/wp_about/biology.html