There are two sources of feather color: pigments and the physical structure of the feather. Many feathers are colored by a combination of these features.

Like paints, pigments are chemical compounds that absorb certain wavelengths of light while reflecting others. The colors you see are those reflected back. Feathers colored by pigments range from crow black to canary yellow and cardinal red. Cardinal feathers stay red when you crush them or dunk them in water.

Many colors, such as blue, are a result of feather structure. Natural white light is a blend of many different wavelengths - each with its own characteristic color. When light hits these feathers, it hits microscopic structures on the feather that act as prisms to bend, scatter, and reflect a color. No blue pigment is known in birds. If you crush a blue Scrub Jay feather or dunk it in water it will appear gray.

Shimmering iridescent colors such as those found in hummingbirds and peacocks are caused by special structures, air bubbles, or films on feather surfaces. These modifications interfere with the bending and scattering of light to strengthen some wavelengths and cancel out others.

A flamingo's pink coloring comes from the bird's diet of small crustaceans and algae, which are full of carotenoid pigments. Captive flamingos may lose their bright colors without special dietary supplements.

Unlike many animals, birds can distinguish colors. Birds use colors and patterns to communicate with each other. These may send messages of aggression, attraction, or alarm. Birds can recognize members of their own species by their color patterns, just like uniforms identify sports teams. Many species attract mates or defend territories with the help of flamboyant advertising plumage. The parent (or parents) with the major responsibility for tending the eggs and the young usually lacks these bright colors, a means of avoiding attracting the attention of predators of eggs or young birds.