Harriman Lake, Jan 4 – with Chuck Aid

Rough-legged Hawk topography (c) Bill Schmoker

Nice mild weather prevailed on Saturday as we enjoyed a 1.6-mile stroll around Harriman Lake.  It was more than half frozen over, but that was perfect as it concentrated all the ducks a bit more and provided a nice shelf of ice for a local immature Bald Eagle.  In order to talk a bit more about plumages of Bald Eagles we need to learn a bit more about bird topography.  If you will look at the diagram, you can see that the coverts are the smaller feathers that cover the bases of the larger flight feathers – the primaries and secondaries.  There are upper-wing coverts and underwing coverts.  There are also upper and lower tail coverts that cover the bases of the main flight feathers in the tail.  I’ve labeled two other parts because they can be important terms for the identification of other raptors.  The carpal is the “wrist” of the bird, and some birds, such as the Rough-legged Hawk in this photo have a distinct carpal patch.  The patagium is the leading edge of the wing, and this can be important because to varying degrees all Red-tailed Hawks have a dark patagium.

Bald Eagle – 2nd year (c) Bill Schmoker

So, back to our Bald Eagle. It takes Bald Eagles five years to obtain their full adult plumage with the white head and tail.  During their first year they have dark brown eyes, a dark bill, and are mostly brownish overall.  During subsequent years the eyes become light brown and eventually yellow, the bill too becomes increasingly yellow.  The plumage during the intermediate years can be quite variable but tends toward a brown and white mish-mash.  For example, a first-year bird tends to have a brown belly with white underwing coverts; most second-year birds develop a white belly with extensive white underwing coverts and some white in the underwing secondaries and tail; third-year birds tend to have darker bellies than second-year birds and the underwings, while still having some white blotchiness, are darker; fourth-year birds are tending towards full adulthood with a blackish-brown belly having some white flecking, and the hood and tail are mostly white but not completely. Our bird on Saturday was a second-year Bald Eagle, much like the bird in the photo but with more white above the eye. To cut to the chase, second-year birds have more white on the body and underwings than any other year.

Best of luck with all your upcoming raptor identifications!

Chuck

 

Harriman Lake, Jan 4, 2020
26 species

Canada Goose  125
American Wigeon  12
Mallard  7
Canvasback  2
Redhead  44
Ring-necked Duck  1
Lesser Scaup  2
Bufflehead  6
Common Goldeneye  4
Hooded Merganser  15
Common Merganser  1
Pied-billed Grebe  4
Eurasian Collared-Dove  1
American Coot  160
Ring-billed Gull  3
Bald Eagle  2 (1 adult and 1 2nd-year)
Red-tailed Hawk  2
Northern Flicker  4
Blue Jay  7
Black-billed Magpie  6
American Crow  4
Common Raven  1
Black-capped Chickadee  2
European Starling  7
Song Sparrow  3
Red-winged Blackbird  40

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