June 13 & 15: Immature Bald Eagle in vicinity of nest

classic Classic list List threaded Threaded
2 messages Options
Reply | Threaded
Open this post in threaded view
|

June 13 & 15: Immature Bald Eagle in vicinity of nest

NewMexiKen
Administrator
On Sunday (June 13) at about 7:40 AM, Luis reported seeing the adult female (Jewel) and also an immature eagle at the corner of Pines Blvd & 208th Ave. He thought the bird was not a juvenile but rather one from the previous season or two.

This morning, while i was walking in the west Miramar wetlands about 1 1/2 miles SE of the nest, an immature Bald Eagle passed almost directly overhead at 6:55 AM. It was flying from west to east and was being pursued by 3 Fish Crows, one of which flew very close to the eagle.

The light was poor but my photos show some characteristics which help determine the age of this eagle, which may or may not be the same one seen by Luis. Immature eagles usually fly north about this time of year. This particular bird appears to be molting into "second year" plumage, meaning it is about 1 1/2 years old.

Note the ragged trailing edges of its wings, caused by worn juvenile feathers which are being replaced by shorter "third year" feathers. The fresh feathers have white patches. Three of the primary feathers in the right wingtip have already been replaced. Others are starting to fill in the longer secondary flight feathers, which produce a bulge evident in the trailing edge close to the body of first year (juvenile) plumage.

Also the wing linings (underwing coverts) are mostly new and whiter than in juveniles, where white is more confined to the "wing-pits" (axillary feathers). The white feathers also extend over the belly  while the upper chest remains dark. With age the bill becomes more yellow and eyes lighten up from black to brown and finally yellow in older eagles, but this is hard to determine. Head will develop white streaks which are more evident in third year plumage.










Reply | Threaded
Open this post in threaded view
|

Re: June 13 & 15: Immature Bald Eagle in vicinity of nest

NotToofast
Beautiful pictures! Thanks a lot for the trove of information. I have seen also an "immature" a little bit to the south of where you report the sighting of this one...
By the way, those pesky crows are always mobbing bigger raptors...I remember a pic on National Geographic showing a crow "landing" on the back of a bald eagle mid-air...