After a massive bird hunt, a research team from Cornell University reported last month  they had sighted an Ivory-billed Woodpecker -- a stately bird many experts believed had become extinct. But one scientist wants more proof. He wants to hear the bird sing.

The Ivory bill is an enormous bird, with a 1 meter-wide wingspan, a brilliant white bill and black plumage. Sound of the bird was last recorded in 1935.

Donald Kroodsma

Renowned ornithologist Donald Kroodsma says visual images of the Ivory bill tell just part of the story. "I want to hear those unique calls just to know for sure, for absolute sure, that it is still with us," he says. "I am a little troubled given the massive manhunt that they have put on in these southern swamps that they have not heard this bird more. I want to hear it."

Donald Kroodsma explores why birds sing and how to better understand their songs in his new book, The Singing Life of Birds. The males mostly do the singing. They sing both to defend their territory, but also - and more importantly - says Donald Kroodsma - to attract fertile females. "I think of it as a competing songfest. The females are listening, making choices, and the males never know when the females are listening," he says. "So, even though she doesn't sing, she is really the composer of this whole orchestra. He is the performer. But he is just singing what she is demanding."

Donald Kroodsma - who is known to sit on the roof of his house early in the morning on spring days to record birdsongs - says birds speak their minds. The other day he

Chipping Sparrow

stepped out his back door to eavesdrop on the conversation of two male Chipping Sparrows. "Hearing those two identical songs from these two males just told of their life story," he says. "It told where that young bird was getting its song. It said how old it was. It said where he is setting up his territory, the special relationship that this young bird had with the older bird. They are telling their stories."

Donald Kroodsma says tuning in to those tales takes practice. He suggests starting with a single bird and listening to the musical repertoire.

The bird kingdom has 10,000 species. Some birds recite long, complicated, seemingly never-ending phrases, while others sing for a few short seconds. Some learn their songs from family. Others mimic the dialogue of neighbors.

Wood Thrush

The Singing Life of Birds - part field guide and part diary - includes an audio CD and picture voiceprints for 30 birds in North America. Asked to pick a favorite, Donald Kroodsma turns to the Wood Thrush, which, because it has 2 voice boxes, sings in harmony.

Donald Kroodsma says The Singing Life of Birds is about connections, not only among songbirds, but also between humans and the natural world. He hopes the book helps people to focus more carefully on that world and to work to ensure its healthy future.