Most avian colors are the result of different types of pigments that are deposited into the developing feather. However, pigments alone do not produce all avian feather colors. Blues and whites typically result from small changes in feather structure that alters their light reflective properties. These fundamental modifications cause blue light to be selectively reflected from the feather surface in the case of blue feathers, while white feathers reflect all visible light. In short, blues and whites are structural colors, or schemochromes.
Visible light is composed of many colors of light, each with distinct wavelengths.
When visible light encounters particles with the same diameter or larger than its component wavelengths, those specific light photons are reflected. Such reflected light photons are collected and seen by the observer's eye, thereby imparting color to the perceived image. Because blue light has a very short wavelength, it is selectively reflected more easily than other colors of light with longer wavelengths. Tyndall scattering can be demonstrated at home using a simple experiment to produce a pale Tyndall blue color. First, mix one or two drops of milk into a glass of water then place this glass in a dark room and focus a flashlight upon it, and the fluid will appear bluish.