By Susan Milius
To learn a song, young white-crowned sparrows don’t need to hear the entire tune straight through. Hearing it in two-phrase bits will do. If the order of phrases in a pair is reversed—BA and DC instead of AB and CD for instance—the sparrows put together the song in reverse, Gary J. Rose of the University of Utah in Salt Lake City and his colleagues report in the Dec. 9, 2004 Nature. Play the same phrases without pairing them, however, and the young birds end up singing a jumble.
Researchers have known that songbirds need to hear singing very early in life if they’re going to learn songs correctly. Youngsters first babble softly and then sing muddled but more-recognizable song snatches until full adult singing emerges. For years, scientists have been working to tease out the details by which early exposure to song creates a neural template for a lifetime of avian crooning.