These photos were taken in on the west side of the Bitterroot Valley on the first day of March. The immature bald eagle is has a large head with thick black bill. Dark brown overall with extensive white mottling on belly and wings. White streaks on crown. Aging Bald Eagles from Adult (5 years or older), 4th, 3rd, 2nd and 1st year. Adult: Bright white head, neck and tail. Dark brown body and wings. Bright yellow beak. 4th yr: Dingy white head, neck and tail. Scattered white marks on body and wings. Yellow bill with dark smudges. 3rd yr: White belly, white wing-pits, white wing-linings, white triangle on back. Bill more gray than yellow. Smooth (regular) trailing edge of wings, except for perhaps one long secondary flight feather. 2nd yr.: Similar to third year, except the trailing edge of wings is ragged; about half of the flight feathers are shorter than the others. Bill is medium gray. 1st yr.: Dark head, dark brown breast, lighter brown lower body, no white triangle on back. White wing-pits and wing linings. Smooth trailing edge to the wings Upper wings are two toned brown. Bill is dark gray. . Reference - Aging Bald Eagles, William S. Clarke