Here are several of the Golden Eagles seen migrating in this morning’s stiff north-northwest wind along Second Mountain in Lebanon County, Pennsylvania.
A hatch-year Golden Eagle, also known as a first-year or juvenile bird. After December 31 of the year of its birth, it will be known as a second-year Golden Eagle.
A hatch-year Golden Eagle reveals no molt of its juvenile flight feathers. Neat and trim.
A hatch-year Golden Eagle displays faded median secondary upperwing coverts, but not the ofttimes mottled tawny “bars” seen on birds after their first year, such as the individual shown in the last image of this post.
A second-year Golden Eagle, also known as a Basic I immature bird.
The same second-year Golden Eagle, just beginning molt of the juvenile flight feathers in the wings.
The second-year Golden Eagle passes the lookout.
Two views of a third-year (maybe older) Golden Eagle, topside (left) and underside (right). Note the conspicuous tawny bars on the topside of the wings (present in all birds after their first year) and a trace of white in the tail (present in birds prior to adulthood). The two-toned appearance of the underside of the wings resembles that of a Turkey Vulture and is an adult trait Golden Eagles begin acquiring as early as their third year. Some birds in their third year retain noticeably longer juvenile secondaries, making the trailing edge of the wings appear jagged.
To learn more about determining the age of a Golden Eagle on the wing, click the “Golden Eagle Aging Chart” tab at the top of this page, then get to a hawk watch and have a look.