Studying Feathers: How do scientists use Tinbergen’s four questions?
We’ve just used Tinbergen’s approach to look at feathers from several different perspectives—but it’s not just a learning exercise. Scientists like those in the evo-devo crowd, are making discoveries in just the same way, by linking findings from across the biological disciplines.
One such scientist is Kim Bostwick, who used this integrated approach to untangle the mysteries of a bird whose feathers work like a musical instrument. This may sound like an outrageous idea, but male Club-winged Manakins of Central and South America use a highly modified feather structure to play a powerful one-note tune. Strong evolutionary pressure on these males to attract females has made them unique in the bird world, but it took years of scientific investigation by Bostwick and colleagues to work out the full story of how and why these birds sing with their wings.
So how do they do it? Club-winged Manakins sing with their wings by rubbing specialized feathers together. One of these feathers is club-shaped with ridges along its edge. The adjacent feather is slender, and bent at a 45-degree angle. This bent feather acts as a pick, while its ridged counterpart acts as a comb to produce a one-note song. This method of producing sound is called stridulationstridulation:stri-du-LAY-shunthe act of rubbing together body parts to make a sound and also occurs in insects, such as crickets.
Kim Bostwick began her study of Club-winged Manakins by asking questions about how they sing with their wings. She spent years piecing together how the birds accomplish this feat mechanically, but she did not stop there. Because Kim had always been interested in evolution, she also asked questions about how their specialized feathers and associated behaviors evolved. This led her to study other birds closely related to Club-winged Manakins to see what behavioral innovations occurred in their evolutionary history that contributed to the display we see today. It turns out that the behavior evolved through a series of small steps, including short wing clicks and backwards hopping, into one of the most unusual displays in the animal world. Like Niko Tinbergen, Kim is one of the many scientists who prefer to ask scientific questions from many angles, going beyond the mechanics to make discoveries about function, development, and evolution.
To learn more about Kim’s story: www.singingwings.org
1. Heinsohn, R., Legge, S., & Endler, J. A. (2005). Extreme reversed sexual dichromatism in a bird without sex role reversal. Science. 309(5734), 617–9.
2. Perrone, M. (1981). Adaptive significance of ear tufts in owls. The Condor, 83(4), 383.
3. Prum, R. O., & Brush, A. H. (2002). The evolutionary origin and diversification of feathers. The Quarterly Review of Biology, 77(3), 261–295.
4. Zelenitsky, D. K., Therrien, F., Erickson, G. M., DeBuhr, C. L., Kobayashi, Y., Eberth, D. A., & Hadfield, F. (2012). Feathered non-avian dinosaurs from North America provide insight into wing origins. Science. 338(6106), 510–4.
Suggested citation: Cornell Lab of Ornithology. 2013. All About Feathers. All About Bird Biology <birdbiology.org>. Cornell Lab of Ornithology, Ithaca, New York. < add date accessed here: e.g. 02 Oct. 2013 >.
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