 To serve courtship and territorial competition, many male hummingbirds have plumage with bright, varied coloration resulting both from pigmentation in the feathers and from prismal cells within the top layers of feathers of the head, gorget, breast, back and wings.When sunlight hits these cells, it is split into wavelengths that reflect to the observer in varying degrees of intensity, with the feather structure acting as a diffraction grating.Iridescent hummingbird colors result from a combination of refraction and pigmentation, since the diffraction structures themselves are made of melanin, a pigment, and may also be colored by carotenoid pigmentation and more subdued black, brown or gray colors dependent on melanin.