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This plate is designed to show the markings of adult and sub-adult bald eagles.Identifying an adult bald eagle isn’t too difficult–most people easily recognize their distinct coloring: the white head, yellow beak, and blackish body and wings — but immature bald eagles are another story. They take years to develop the signature “look” of a bald eagle with 1st-year birds being mostly dark brown with white wing pits and white underwing coverts. 2nd-year birds are still mostly dark overall, but are variable with white bellies and white upper backs. 3rdyear birds typically have a mix of white and dark on the belly and upper back and show some white on the mostly dark head. 4thyear birds are mostly dark on the belly and back with a whitish head and dark eyeline, and a whitish tail with a dark tip and faint dark streaks. The head and tail become whiter and the eyes and bill become yellow as Bald Eagles reach adulthood, but 5th and sometimes 6th-year birds often still have specks of dark around the eye or on the tail tip, or white on the axillaries or underwings.
Using a composite plate like the one above allows the authors to provide direct comparisons and to highlight the subtle changes that occur in immature bald eagles through the first 4-6 years of life.