INNATE TEMPLATE DIFFERENCE COULD INDUCE SIGNAL COMPLEXITY: A COMPARISON OF SONG FEATURES UNDER AUDITORY ISOLATION BETWEEN WILD AND DOMESTICATED FINCHES

摘要

Bird songs are acquired by vocal learning. Mechanism and evolution of birdsongs partly parallels those of human language. Songs of Bengalese finches, which are composed of complex sequence, have been studied as a key to understand evolution of signal complexity. Bengalese finches are domesticated from wild white-rumped munias. Songs of domesticated finches contain more tonal sounds and complex note-to note transition than those of wild strains (Okanoya, 2004). Takahasi & Okanoya (2010) found differences in learning property between the two strains using a cross-fostering paradigm. Wild finches imitated a conspecific tutor's song more precisely than domesticated finches do. However, domesticated finches imitated both tutor's songs roughly equally. The domesticated strain may produce their own songs based largely on innate template. Auditory isolation experiments enable us to examine the genetic contribution to song learning. We examined the songs of isolated and normal birds from both strains in order to compare characteristics of innate templates.