Figure 18.

Examples of colorful feathers in birds. (a) Female silver-breasted broadbill (Serilophus lunatus, Eurylaimidae). (b) Male eastern bluebird (S. sialis, Turdidae). (c) Male plum-throated cotinga (Cotinga maynana, Cotingidae). (d) Scanning electron microscopy photograph of the basic nanostructure with a thin (≤1 μm) disordered layer of spongy β-keratin bars, at the periphery of medullary barb cells from the pale blue-grey primary covert feathers of S. lunatus, (e) Transmission electron microscopy photograph of the channel-type nanostructure made of β-keratin and air in the barb cells from the royal blue contour feathers of S. sialis. (f) Transmission electron microscopy photograph of the sphere-type nanostructure made of β-keratin and air in barb cells of the dark turquoise blue contour feathers of C. maynana. Scale bars: (d) 250 nm; (e,f) 500 nm. Photo credits: (a) Yiwen Yiwen; (b) Ken Thomas; and (c) Thomas Valqui [263]. © The Royal Society Publishing.