Recordings of ivory-billed Woodpeckers

Cornell researchers have released audio recordings they say is more evidence that the Ivory-billed Woodpecker, long thought to be extinct, is alive and well in Arkansas. (Background here and here.) The ornithologists analyzed more than 18,000 hours of recordings to come up with what may be the woodpecker's signature knocks and calls. From Cornell University News Service:
The recordings reveal sounds that, experts say, are strikingly similar to those made by ivory-billed woodpeckers and provide compelling information that can be added to evidence already gathered of the bird's existence. One of the recordings, from Jan. 24, 2005, captured a distant double knock, "Bam bam!" followed by a similar and much closer double knock 3.5 seconds later -- possibly the drumming displays of two ivory-billed woodpeckers communicating with one another by rapping on trees.

"I immediately felt a thrill of excitement the first time I heard that recording," said Russell Charif, a bioacoustics researcher at the Cornell Lab of Ornithology. "It is the best tangible evidence so far that there could be more than one ivory-bill in the area."
Link to "Listening for the Ivory-bill," Link to the news article