Double Knocks from the Big Woods of Arkansas
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
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