SICB Division of Ecology and Evolution (DEE)

DEE Researchers Database Entry

Kimberly Bostwick

How birds make sounds with their wings and how did it evolve
I study a little-known phenomenon called sonation (as opposed to vocalization) in birds. My research combines behavior, anatomy, field work, and lab work to understand how birds make sounds with their wings, and how this odd phenomenon has evolved. I have focused on the Neotropical Manakins, Pipridae, because they are among the most amazing sonators in the animal kingdom. The species pictured here, the Club-winged Manakin, Machaeropterus deliciosus (A), is possibly the most specialized species of sonating manakin. As Darwin noted in 1871, male Club-winged Manakins have extremely modified wing feathers for sound production. Normal feathers have very narrow shaft (B, feather on the left) while the same feather in the Club-winged Manakin has a very wide feather-shaft (B, feather on the right, shafts shown in red). High-speed video has shown these birds make sounds by knocking their wing-feathers together over their backs (C). The sound produced is unique in consisting of a fundamental tone with integer-related harmonics that last for ~1/3 of a second. Other species of manakins make sounds in different ways, and because these sounds are produced in the context of courtship displays, I attribute the evolution of these odd traits to sexual selection.