Case studies of song and call learning by a hybrid Bengalese–Zebra Finch and Bengalese-fostered Zebra Finches: Assessing innate factors in vocal learning

Abstract

Vocal learning in birds is limited by both genetic and environmental factors. Innately determined, species-specific ranges of song parameters restrict song structures; the actual parameter values are determined by environmental inputs during learning. This is also true for some call notes. Here, we investigated the characteristics of songs and distance calls in a hybrid Bengalese–Zebra Finch and Bengalese-fostered Zebra Finches. The Bengalese-fostered Zebra Finches learned a limited part of the song elements, whereas the hybrid learned most of the foster father's song. However, the hybrid could not learn the acoustic morphology of Bengalese distance calls as well as the fostered finches. The results suggest that the neural circuitry for song element repertoire and call acoustic morphology are independent and that hybridization and cross-fostering procedures are useful tools for investigating genetic and environmental factors in vocal learning.