Nice morning with good light and calm winds. Watched the bird for about 10 minutes as it slowly swan further out away from dam. First saw it about 50 yds. out. Was using a Zeiss Victory 20x60 scope.
DID YOU TAKE NOTES?
No, not at all
DID YOU CONSULT A FIELD GUIDE OR OTHER REFERENCE WORK?
Yes, during the observation
WHICH GUIDE(S) OR REFERENCE(S): DID YOU CONSULT?
Sibley Guide to Birds that I always carry in my car.
DESCRIPTION OF THE BIRD(s)
In the duck family. The medium-sized swimming duck had a rounded head and was darkish overall with whitish cheek area that started below the dark head cap and from back of bill and extended down the neck. The bill was medium-long and thin. I could see tail feathers that extended a little beyond the body.
BEHAVIOR OF THE BIRD(s)
The duck was swimming along the embankment with American coots. I never did see it dive but it slowly kept swimming further out and away from the dam as I watched it.
HOW AND WHEN DID YOU POSITIVELY IDENTIFY THE BIRD, AND WHAT CLINCHED THE IDENTIFICATION FOR YOU?
I clinched the ID as a BLSC when I saw it swimming along with the coots. I had recently tried for a BLSC that was seen in the Boise area and had checked all the field marks for one at that time. The size, shape and coloration of the bird all fit what I had recently been studying.
HOW DID YOU ELIMINATE SIMILAR SPECIES? WHAT WERE THEY?
The male non-breeding Ruddy duck would be the most similar looking species with its darker body and white cheek patch, but this bird was bigger than the American coots it was swimming with and the Ruddy duck would be about the same size as the American coots. Also the bill of this bird was very different from a RUDU. The other 2 Scoter species look a lot different than BLSC having bigger, longer bodies and different shaped bills. And neither of them show a white cheek patch as big as the BLSC.
WHAT IS YOUR EXPERIENCE WITH THIS (AND SIMILAR) SPECIES?
I have had several sightings of BLSC in Idaho, mostly in the Hagerman area, and also along the Pacific coast on birding trips to areas over there. Same with other Scoters species.