Repertoire size, auditory templates, and selective vocal learning in songbirds

Abstract

When vocal variability, here measured by song repertoire size, increases in songbirds, it may become increasingly difficult to encode genetically all the information which is required to ensure the learning of only conspecific songs. Marsh wrens ( Cistothorus palustris) have sizeable song repertoires, and while no vocal mimicry is evident in the field, males will readily learn heterospecific songs in the laboratory. These data, together with data from the literature, support the proposed relationship between increased repertoire sizes and reduced specificity of the innate auditory template which guides vocal learning.