杏吧原创

SOUND recordings have convinced sceptics that a pair of ivory-billed woodpeckers survive in the White river area of Arkansas.

The reported rediscovery of the striking but shy bird made headlines at the end of April because it had not been seen in the US for more than 60 years. However, careful examination of blurry videotapes and photographs failed to convince Richard Prum, an ornithologist at Yale University, that the spotters had found the right bird. Prum and two colleagues drafted a paper warning that the claims of rediscovery might be mistaken.

But Prum changed his tune when he heard audio recordings made by the ornithologists at Cornell University in Ithaca, New York, who had rediscovered the bird. 鈥淚 was really stunned and excited,鈥� he says. He recognised the ivory-bill鈥檚 distinctive nasal 鈥渒ent鈥� call, which had been preserved on recordings from the 1930s. He also heard a distinctive pattern of two birds 鈥渄ouble-rapping鈥� 鈥� each tapping twice on the tree it was perching in.

The telltale sounds came from 17,000 hours of recordings the Cornell group had collected. Team member Tim Gallagher says they hadn鈥檛 found the ivory-bill sounds when they rushed their initial report into print. 鈥淚 totally understand the scepticism,鈥� Gallagher says. 鈥淚f I were on the other side I would be sceptical too.鈥�