He and the students in his lab use the songbird—and in particular, the zebra finch—to study mechanisms of vocal learning. Like a human infant first beginning to babble, the young zebra finch learns to imitate complex sounds during a critical period of development. Why the adult bird loses the ability to imitate is still a mystery. The lab uses brain imaging and sound analysis to better understand the bird's behavior and the dynamics of vocal learning. In addition, the lab aims to uncover the specific genetic and physiological processes that underlie song learning.