The ability to use learned, symbolic vocal gestures for social communication lies at the
cornerstone of human sociocultural activity. To date there is no nonhuman animal model of
human grammatical speech; however, humans are not unique among vertebrate species in
possessing the ability to use learned vocal getures to coordinate social behavior. The ability
to use learned vocal signals for coordinating important reproductive and social behaviors is
well developed in many species of birds and exhibits important parallels with that of …