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Mann, NI,
KA Dingess, KF Barker, JA Graves, & PJB Slater (2009) A comparative
study of song form and duetting in neotropical Thryothorus wrens. Behaviour 146: 1-43.
The traditionally-defined wren genus Thryothorus is notable for its
diversity of singing styles with some species producing highly coordinated duets
or choruses in various formats while, at the other extreme, songs are performed
almost exclusively by males. In this comparative study, we document the singing
styles of almost all of the 27 or so species in this group, relating these to a
molecular phylogeny in an effort to identify the conditions that have led to the
evolution of duetting and chorus singing. In a previous study, we used molecular
data to demonstrate that Thryothorus is actually paraphyletic, leading us
to propose its splitting into three genera (one newly described) in addition to
Thryothorus. Here we show that most species within each of these four
genera usually sing with the same style, and that these styles tend to differ
between the genera. We also show that a few species have songs that differ
markedly from those most typical of their genus. We argue that these exceptional
cases will provide important insights into the origins of duetting behavior, and
tentatively suggest factors that may have played a role in determining the
extent to which male and female birds combine their vocalizations
together.
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