The whistling pecker split off from the plentpecker to find more food. It didn't change very much except for the fact that it no longer relies on the pleppo for food. They developed a small inflatable sac on their butt-nostril which produces a whistling sound that emanates from their butt-nostril to attract females. During mating season, the males engage in a whistling competition. The female will select the one that can whistle the longest.