Researchers have found a new way to create colors! Throughout history, pigments have been used whenever color was needed. However, researchers have discovered that birds create color by means other than pigment! Unlike human hair, feathers never turn grey. Instead, birds actually control the nanostructure of their feathers, changing the size of holes in the keratin material. This determines how the light is scattered, and therefore the color that is reflected. When the holes are larger, the wavelength reflection creates the color white. When the holes are smaller, the result is blue.
Looking at an individual feather barb, there are many different colors along the length. The discovery of this way of creating colors has inspired researchers to explore how paint and clothing might be colored in the same way, by adjusting the density and size of the holes of the material. A paint made this way would never fade, would be environmentally friendly, and would be less toxic than many pigments. Interestingly, this research in bird feathers answers a long-standing question about the color green. Noniridescent greens are rare in nature - because the color green is a complex narrow wavelength that is hard for such creatures as birds to produce. To get around this, birds mix in some yellow pigment with the structurally created color blue!