Song Dialects of Wrens (Troglodytes troglodytes) in Three Districts in Japan

Author(s): Hisataka Fujimoto, Taku Hasegawa

Vocal signals, including spoken languages and birdsongs, are composed of a finite number of acoustic elements, including repetition, which is composed of a combination of these elements linked together by syntactic rules. While songbirds follow specie-specific syntactical rules, they often show regional dialects presumably due to the acquisition process of their songs. Many previous studies have examined migratory birds that seasonally traveled abroad; thus, it is unclear whether the dialects are restricted within the geometric regions. Here, we examined the songbird wren (Troglodytes troglodytes), which is a sedentary songbird with one of the most complex songs, in three areas: Mount Aso (Kumamoto Prefecture, Japan), Mount Ishizuchi (Ehime Prefecture, Japan), and Mount Daisen (Tottori Prefecture, Japan). We examined ten birds in each area and identified each bird using binoculars, and syntactic differences associated with geometric regions, or dialects, were investigated. The male wrens in the Mount Daisen dialect sang with little or no continuation of the different types of trills. On the other hand, male wrens in Mount Aso and Mount Ishiduchi frequently and continuously sang two or more different types of trills. All birds used trills and whistles. Our results suggest that sedentary songbirds, in addition to migratory birds, have dialects in song syntactic structure.