Song Syntax in Bengalese Finches: Proximate and Ultimate Analyses

Abstract

Publisher Summary This chapter discusses the song syntax in Bengalese finches. Bengalese finch song has a unique type of complexity. The syntactical rules underlying it by statistical methods are analyzed and found that the songs of these birds could be expressed as finite state syntax. In general, two to five song notes are arranged in fixed order to form “chunks” and several chunks are arranged with probabilistic rules into variable song phrases. Through song development, it is found that the phonological characteristics appeared first and syntactical characteristics were then established. The song development follows the hierarchical path from song phonology to song syntax. To understand the evolution of the song complexity, songs of the wild strain of the Bengalese finch, the white-backed munia are examined. Their songs are linear strings of notes in a highly stereotyped order, neither hierarchical nor complex like those of Bengalese finches. The brain mechanism by which this complex syntax was enabled is investigated in the chapter. It is suggested that song complexity in Bengalese finches may have been initiated as a sexually selected trait in the wild, and then enhanced in a domesticated environment that relaxed several selection pressures in the wild.