Eagles are powerful birds of prey, often recognized by their impressive size and commanding presence. While adult eagles, such as the Bald Eagle with its distinctive white head and tail, are widely familiar, their younger counterparts display a remarkable range of appearances. These young birds undergo significant transformations in plumage, eye color, and beak color as they mature.
Appearance of Nestlings and Fledglings
Eagle life begins in the nest, where hatchlings emerge covered in a light gray or white natal down. This initial fluffy covering provides warmth but offers little insulation. Around two weeks after hatching, this natal down is replaced by a darker, gray thermal down, which offers better insulation. As they grow, black and brown feathers begin to emerge, typically around five weeks of age.
By ten to twelve weeks, eaglets are largely covered in their first true feathers, though their tail and wing feathers may still be relatively short. At this stage, they are known as fledglings, preparing for their first flight from the nest. Their beaks are initially black, and their eyes are dark brown. For Bald Eagles, the gape (corner of the mouth) may show a yellow tint even at this early stage.
The Juvenile Transformation
Upon taking their first flights, young eagles enter their juvenile phase, displaying a distinct plumage that differs significantly from their adult form. Juvenile Bald Eagles are predominantly dark brown, often appearing almost black across their entire body. This dark coloration may include some white flecking, particularly on the underside of their wings and belly.
The beaks of juvenile Bald Eagles remain largely dark, though some yellow may be present at the gape (fleshy base of the beak). Their eyes are a dark brown, contrasting with the lighter, often yellow eyes of mature eagles. In flight, first-year Bald Eagles have noticeably wider and blunter wings compared to adults, sometimes described as looking like a “flying door.” This plumage is worn for about six months before their first molt.
Subadult Plumage Stages
Eagles transition from juvenile to adult plumage through multi-year molts, a process taking up to five or more years for Bald Eagles. After the first six months, the dark juvenile plumage of a Bald Eagle begins to lighten, with more white flecking appearing on the breast and underwing. During their second year, their belly may become mostly whitish with brown flecks, while the head and breast often remain dark, creating a hooded appearance. The beak starts to show more yellow, and the eyes begin to lighten from dark brown to a paler brown.
In the third year, Bald Eagles show variable plumage, with some remaining dark and others developing a mostly white belly. The head often begins to whiten, though it may still contain brown flecking, sometimes forming a dark stripe through the eye. The beak becomes increasingly yellow, and the eyes continue to lighten. By the fourth and fifth years, the head and tail progressively become whiter, with less brown mottling, and the beak typically turns fully yellow. Golden Eagles also mature over four to five years, with white wing and tail patches gradually turning dark brown as they age.
Key Distinctions for Identification
Identifying young eagles requires attention to specific visual cues. Juvenile Bald Eagles can be mistaken for Golden Eagles due to their overall dark brown coloration and lack of a white head and tail. A key distinction for Golden Eagles, regardless of age, is a golden hue on the back of their head and nape. Golden Eagles also have feathers extending down their legs to their feet, unlike Bald Eagles whose legs are unfeathered above the feet.
In flight, juvenile Bald Eagles possess broad, flat wings held level, with blunt tips. They often display white “wingpits” or mottling on the underside of their wings. Juvenile Golden Eagles, conversely, exhibit well-defined white patches at the base of their primary flight feathers and a broad white band on their tail, contrasting with a dark terminal band. While both species are large, Bald Eagles tend to have proportionally larger heads and heavier bills compared to Golden Eagles.