Known sounds of the Ivory-billed Woodpecker

In his classic 1942 study of Ivory-billed Woodpeckers, James Tanner wrote that "All the ivory-bills that I have ever seen I located first by hearing them call and then going to them." Ivory-billed Woodpeckers are known to produce two types of distinctive sounds: vocalizations and double knocks.

Vocalizations (calls)

The ivory-bill's vocalizations are short nasal-sounding toots, often described as sounding like a child's tin horn. Only one set of recordings positively identified as ivory-bill calls has ever been made,totaling approximately five minutes. In April 1935, Arthur Allen and colleagues from Cornell recorded a mated pair of birds at a nest in the Singer Tract in Louisiana.

A single note of the ivory-bill is most often described as sounding like "kent," though such written phonetic representations don't convey very well how the note actually sounds.

The sound spectrogram below shows four kent notes from the 1935 Allen-Kellogg recording of two Ivory-billed Woodpeckers in the Singer Tract, Louisiana. Note the distinctive ladder-like pattern of harmonics. Click on the play arrow on the lower-left  beneath the spectrogram to hear the sounds.

Seeing sounds

The images of sounds on this website are called sound spectrograms. Like a musical score, a spectrogram represents time horizontally, from left to right, and frequency, or pitch, vertically. More information about sound spectrograms is available here.

Double knocks

The ivory-bill's other characteristic sound was never definitively recorded, and is known only from written descriptions: a loud, rapid, double knock made by two strikes of the bird's bill against a tree, apparently used as a display, alarm, and contact signal. Other Campephilus woodpeckers produce similar display drums.

The sound spectrogram below shows a double knock recorded from the Pale-billed Woodpecker (Campephilus guatemalensis), which lives in forests of Central and South America. Click on the play arrow to listen to the sound.



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