Winter Wren Singing Behavior: A Pinnacle of Song Complexity

The songs of the Winter Wren in North America are long and complex, but consist of highly organized and repeatable sequences of different song units. Eastern and western populations differ markedly in complexity of song types and overall repertoire size. Two eastern males sang only two song types, while one intensively studied Oregon male sang at least 30 stable song types; temporal and frequency parameters also gave the impression of greater complexity within Oregon songs. At both locations, though, neighboring males sang nearly identical song units or (especially in New York) entire songs, indicating that vocal learning is fundamental to song ontogeny. The complex song of the Winter Wren may be a product of intense sexual selection in a polygynous mating system, but further data on both mating systems and song complexity in different populations are needed before this hypothesis can be critically assessed.