Figure 1.

Spectrogram of the presumptive victory display (duet type 5) and photograph showing a pair of duetting tropical boubous, Laniarius aethiopicus. Only the initial three repetitions of the duet are shown. Males always sing the top notes, females the bottom notes.

Grafe and Bitz BMC Ecology 2004 4:1   doi:10.1186/1472-6785-4-1
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