DAVID GREENE, HOST: This program does bring you sounds of the world, and that includes the sound of a bird outside a home in Boone County, Mo.</s>DAVID GREENE, HOST: We're hearing this courtesy of Sue Rettinger (ph). She sent it as part of our series, Decoding Nature. She writes, I heard this bird song starting in May. The bird sang every day. He's apparently left the area now, for I haven't heard him since mid-July.</s>STEVE INSKEEP, HOST: So we have two questions. What's singing that song, and why did it stop? For answers, we turn to Jessie Barry at the Cornell Lab of Ornithology.</s>JESSIE BARRY: When you hear these beautiful flute-like whistles with this kind of catchphrase in the middle, that's a little ee-oh-lay (ph), that's the sign of a wood thrush.</s>DAVID GREENE, HOST: So a wood thrush was singing. The next question, why did it stop?</s>JESSIE BARRY: Throughout the breeding season, they'll keep up that song to defend their territory and attract a mate. But once the chicks are out of the nest, the adults will go quiet. By, you know, middle of August, they start to go on their migration, heading towards Central America.</s>STEVE INSKEEP, HOST: Chicks out of nest, adults quiet. Keep that in mind. Thanks to Jessie Barry of the Cornell Lab of Ornithology for decoding that mystery.</s>DAVID GREENE, HOST: If you have a backyard nature sound that you would like us to decode, record at least a minute and send the file to nprcrowdsource@npr.org with the subject line, decode nature, and also your location.</s>STEVE INSKEEP, HOST: And for more on this subject, follow the hashtag #DecodeNature on Twitter.
We asked listeners to record sounds of backyard wildlife and invited the experts at the Cornell Lab of Ornithology to identify them. Today's mystery sound comes from a listener in Boone County, Mo.