Science 320, 630–634 (2008)

The babbling calls of baby songbirds involve separate brain circuitry from that used to generate more complex adult song, report neuroscientists at the Massachusetts Institute of Technology in Cambridge.

Michale Fee and his team gave adult zebra finches a drug that stopped the “high vocal centre” — a brain region that enables birds to sing melodious 'syllable' sequences — from working. The birds reverted to the stereotypical babblings of one-month-old chicks within 20 minutes, but regained their tuneful adult song when the drug wore off. Another brain region called the lateral magnocellular nucleus of the nidopallium proved necessary for juvenile babbles but not for adult song.