Iridescent feathers, like those seen in hummingbirds and peacocks, are created through structural coloration. This occurs when microscopic structures in feathers create interference patterns with light waves. The feathers contain layers of tiny, flat plates made of keratin and melanin that act like prisms.
These structures work in several ways:
- Reflect different wavelengths of light at different angles
- Create shifting colors as the viewing angle changes
- Produce metallic sheens and rainbow-like effects
The precise spacing and arrangement of these structural elements determines which colors are produced. For example, the gorgeous throat patches (gorgets) of male hummingbirds appear to change from red to black or purple to blue as the bird moves, all due to these microscopic structures.