The bald eagle gets its common and scientific names from the distinctive appearance of the adult’s head as mature coloration is reached in the eagle’s fifth year.
The bald eagle gets both its common and specific scientific names from the distinctive appearance of the adult’s head as mature coloration is reached in the bald eagle’s fifth year. Bald in the English name is from the older usage meaning white rather than hairless, referring to the white head and tail feathers and their contrast with the darker body, as in piebald. The genus name is New Latin: Haliaeetus (from the Ancient Greek: ἁλιάετος, romanized: haliaetos, lit. sea eagle), and the specific name, leucocephalus, is Latinized (Ancient Greek: λευκός, romanized: leukos, lit. white) and (κεφαλή, kephalḗ, head).
The bald eagles undergoes four distinct maturation stages, each comprising one year of its life.
Immediately after hatching, the bald eagle has dark eyes with pink legs and skin and flesh colored talons. The skin darkens to a bluish hue and the legs become yellow within the first 18 to 22 days of the bird’s life. Throughout the first year, the bodies, eyes, and beak are dark brown, although the underwing coverts and axillaries are white. In the bird’s second year, the eyes lighten, becoming grayish-brown, and they develop a light-colored superciliary line. The body becomes mottled white. During the bird’s third year, the bill and eyes begin to turn yellow and the coloration of the head feathers lighten. The body remains mottled. In the bird’s fourth year, the body becomes mostly dark and the head and tail become mostly white with some beige around the eyes and crown and isolated dark spots on the tail. Finally, mature coloration is reached in the bald eagle’s fifth year.
Although bald eagles obtain their adult plumage during their fifth year, they may continue to have a few dark spots on their head and tail for several additional years.
• Image | ©️ Tony, Some Rights Reserved, (CC BY 2.0)
• Sources | (Alderfer, 2006; Bortolotti, 1984a, 1984b; Dickinson, 2017; Dudley, 1998; Sibley, 2003; Siciliano Martina, 2013; Wikimedia Commons, 2020)