Boughman JW & Moss CF (2003) Social sounds: vocal learning and development of mammal and bird calls. In Megela-Simmons, A., Popper, A.N., & Fay, R. (eds) Acoustic Communication. Springer-Verlag. (Handbook of Auditory Research) pp. 138-224.
We have reviewed data on call learning in birds and mammals for calls that function as individual or group signatures and dialects and focused on call learning rather than song learning.We distinguished two forms of vocal learning – learned acquisition and social modification. We began by predicting when vocal learning was expected and detailing the evidence necessary to demonstrate that vocalizations were learned. Studies should exclude or control factors that can produce patterns similar to those induced by learning, including maturation, body size, genetics, population structure, and local ecology. We then presented case studies for three functional levels: 1) individual signatures: lesser spear-nosed bats, bottlenose dolphins, and Japanese and rhesus macaques; 2) group signatures: chickadees, budgerigars, greater spear-nosed bats, killer whales, and pygmy marmosets; and 3) dialects: Amazon parrots, hummingbirds, humpback whales, and tamarins.
Learned acquisition of calls is rare in mammals, though fairly common in birds. Social modification is more common in both mammals and birds. Social modification of group signatures is particularly prevalent. Too little data are available to carefully test the validity of song learning theories for call learning. This area should receive further attention to evaluate the necessity of sensorimotor input, the existence and duration of critical periods, and the possibility of selective attrition. Social interaction is clearly necessary for most species. The study of call learning in mammals and birds has much promise. Not only can it provide critical insight into the neural, perceptual, and motor mechanisms that underly vocal learning across taxa, but also into the ecological and behavioral factors that favor its evolution. These questions will benefit from putting vocal learning studies squarely in a phylogenetic framework. Vocal learning also has potential to give us insight into cultural evolution, and help us understand how the dual processes of genetic and cultural change influence biological evolution and diversity.