Many of our most beloved birds are those with beautiful coloration, including orioles with their sunny colors and hummingbirds with their iridescent greens. Some of these colors, including red, yellow and orange, are made with reflective pigments which are either synthesized by the bird or are more commonly obtained through their food.
Other colors are created by nanoscopic structures within a feather, including tiny air bubbles found in feather barbs. These nanostructures scatter light in ways that can make the feather appear blue or iridescent. Researchers continue to uncover the ways birds have evolved to structurally color their feathers, including how the keratin cortex thickness of Ring-necked Pheasant feathers produces iridescence, and how wrinkles on Great Argus flight feathers produce a blue-ultraviolet color.