The complex aerial song of the Short-billed Dowitcher (Limnodromus griseus) is described, and recordings from northern British Columbia (subspecies caurinus), northern Manitoba (hendersoni), and Labrador (griseus) are analyzed. The song is a stereotyped sequence of one to five units that are repeated rapidly and increase successively in duration. Each song unit consists of three readily distinguished element types (I, II, III), which form graded series occurring in fixed sequence. Song structure and element types are similar in all subspecies, but significant quantitative differences exist; the central subspecies (hendersoni) is clearly distinguished from the other two, in particular. These geographic differences are slight in comparison with primary song in many species of Oscines.
Geographic variation in song structure in the Hermit Thrush (Catharus guttatus)