Monday, February 2, 2015

Determining the Ages of Bald Eagles

I have been seeing a lot of bald eagles lately; from many birds down east at Alligator River National Wildlife Refuge to some birds right here in Mecklenburg County. Bald eagles take up to five years to attain the classic adult plumage that even non-birders readily recognize. But for the first four years of their lives the plumage can be highly variable.
Below are a few photos of bald eagles in various stages of maturity:

Here is a classic adult eagle. All white head, yellow bill, dark body, and white tail. This bird is at least five years old.

Bald Eagle by Ron Clark

This photo is of one of the nesting birds from Mecklenburg County with the chick. The parent is on the right. Notice the head is almost completely white except for some dark smudginess behind the eye. This is indicative of a four-year-old bird. Almost certainly this was that bird's first nesting attempt. and it was successful!
Juvenile and first-year bald eagles are almost all dark, including the bill. They will retain this plumage for almost a year and a half. The bird on the right is a juvenile bird.

Bald Eagles by Carol Jackson

This is a photo of a bird taken at Lake Norman just a couple of weeks ago. Note the head is becoming very pale but is not yet white.  The darker smudges behind the eye are more extensive than in the fourth year bird above. The body is getting dark but has some scattered white feathers in the wing pits. The bill is not yet all yellow. This is plumage typical of a three-year old bird.

Since sightings of bald eagles in the Mecklenburg County and the surrounding area are increasing, and are likely to increase even more, i thought it might be helpful to remind everyone that eagles can come in a variety of plumages.