Double Knocks from the Big Woods of Arkansas

In more than 17,000 hours of recordings, thousands of double-knock sounds were detected. After eliminating noises made by raindrops, gunshots, and other sources, researchers at the Cornell Lab of Ornithology found about 100 double knocks that sound tantalizingly similar to the double knocks of other Campephilus woodpeckers. Listen to the three examples below.

Double knock, December 25, 2004

Three double knocks, January 24, 2005

Three double knocks, February 5, 2005

Audio Playback Requirements

Two audio formats are in use:
Interactive Analyzer provides the user with advanced playback manipulation capabilities. QuickTime and a free analyzer player are required.

Download the Windows version of the analyzer.
Download the Macintosh version of the analyzer.

Instructions for installing the analyzer:
(1) Download the installer
(2) Quit the browser
(3) Double-click on the downloaded installer
(4) Restart the browser and come back to the sounds page.

Simple Sounds provide fixed sonagram images and RealAudio recordings. A free RealAudio player is available for download.