Why are hummingbirds so colorful?🎨 Hummingbirds are some of the most colorful birds in the world because of the structure of their feathers. The feathers contain organelles called melanosomes that produce pigment and have a flat, disc-like shape with many air bubbles. When sunlight hits the feathers, the light reflects off the melanosomes, which can create shimmering colors that change depending on the viewing angle. This process is called iridescence, and the colors are sometimes called "struc