Fig. 1. Sound spectrograms of putative Ivory-billed Woodpecker recordings and comparison sounds. Sound spectrograms of putative Ivory-billed Woodpecker double knocks (A-F) and kent calls (E, F) recorded along the Choctawhatchee River, Florida in 2005 and 2006. Spectrograms of the double knock of a Pale-billed Woodpecker (D) and a recording of a kent call of an Ivory-billed Woodpecker made in 1935 (G) are shown for comparison. Sound files available through online supporting information. [ERRATUM]