Size Matters

The picture below shows Jim with one of this year’s eaglets. The oldest of the three juveniles was 141 days old on August 13th when this picture was taken. I have previously mentioned here that the feathers of the juvenile plumage are longer than the feathers of the adult birds. The size difference is very well illustrated in Roger’s picture. The juvenile is slightly closer to the camera but they are on the same branch. Furthermore, the juvenile in the picture is very likely a female, Jim’s daughter. Female Bald Eagles are typically taller, broader and heavier than males. If you have caught a glimpse of Jim or Cindy flying with the juveniles then you have been able to compare the depths of the adult and juvenile wings. The difference is obvious.

These longer feathers will eventually be replaced by shorter feathers through future moltings. The resulting mixture of old and new feathers on the trailing edge of the wings and tail is what gives juvenile eagles that jagged, tattered appearance. Eventually all of the longer feathers will fall out. As the eagle matures over the next few years it will gradually develop the nicely manicured look of the adult birds.

Jim and his offspring.

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Published in: on August 16, 2012 at 3:07 am  Leave a Comment  

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