Identifying double knocks made by an Ivory-billed Woodpecker is tricky. The sound is described in the scientific literature by people who heard the display prior to the 1950s, but there are no known recordings with which to compare recent recordings from the Big Woods. Researchers use recordings of double knocks made by other woodpeckers in the same genus, Campephilus, as a best approximation of what an ivory-bill display drum might sound like.
Choose "Interactive Analyzer" to explore the sonogram and see it scroll across the page as the sound plays. When viewing the sonogram, click on the circled i for information about how to use the sonogram features.
Choose "Simple Sounds" for a faster download of a fixed sonogram and an audio file.
Audio Playback Requirements
Two audio formats are in use:
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.