Plumage refers both to the layer of feathers that cover a bird and the pattern, color, and arrangement of those feathers.

In their five year development to adulthood, bald eagles go through one of the most varied plumage changes of any North American bird. During its first four weeks of life, an eaglet's fluffy white down changes to a gray wooly down. At about five weeks, brown and black feathers begin to grow. It becomes fully feathered at 10 weeks of age. In its first year, the mostly dark-colored juvenile can often be mistaken as a golden eagle. However, the bald eagle progressively changes until it reaches adult plumage at five years. Notice in the pictures how its dark eye lightens throughout its first four years of life until it becomes yellow. Also, see how its beak changes form gray-black to a vibrant yellow.

It is believed that the darker, more mottled plumage of a young eagle serves as camouflage, while the white head and tail announce that it is of breeding age.