Macrogeographic Variation in the Song of the Olive Whistler in Australia

Abstract

The macrogeographic variation of the territorial advertisement song of the Olive Whistler Pachycephala olivacea over its range in Australia is described. The existence of this variation between isolated and widely separated populations, and dialect changes in contiguous population groups, demonstrate song learning in this species. In the four isolated populations in the north, with no mutual social contacts, the vocal patterns result from the use of arbitrarily adopted forms of notes or syllables. In the larger population regions, where intermittant social contact occurs, nine dialect regions are identified by the notes and syllables that begin and end the song. The very large changes in the pattern occurring at the western extremity of the range are not explained, but may be due to unidentified environmental factors.