SYNOPSIS. The colors of birds result from deposition of pigments—mainly melanins and carotenoids—in integumentary structures, chiefly the feathers. The plumages of birds indicate their age, sex, and mode of living, and play important roles in camouflage, mating, and establishment of territories. Since feathers are dead structures, change of color of feathers is effected through divestment (molt) and replacement. The color and pattern of a feather are determined by the interplay of genetic and hormonal influences prevailing in its base during regeneration. Most birds replace their feathers at least once annually. Some wear the same kind of basic plumage all the time butothers alternate a basic and breeding plumage, either in one (the male) or both sexes. Still others may have more than two molts, adding supplemental plumage at certain times in the plumage cycle. The varieties of patterns of molt, the kinds of plumage, and the colors and patterns of feathers among birds apparently are the result of several kinds of selection pressures working through evolution.