Sometimes when I take a photo of a bird, I have no idea what kind it is—I tend to shoot first and ask questions later. That was the case last Friday when I spotted this beauty at Belmont Bay, an area of open water at the confluence of the Occoquan and Potomac Rivers in Northern Virginia. Fortunately some more experienced birders on the What’s This Bird Facebook forum helped me identify it as probably a Greater Scaup (Aythya marila), a type of diving duck.
I had tried to identify the bird on my own using a field guide that I have at home and some on-line resources, but I confess that I got stuck. I couldn’t figure out if this was a Greater or Lesser Scaup. Most of the information on distinguishing between the two species is comparative, i.e. the head is narrower or more oval. It’s hard to make a comparison when you see only a single member of a species.
As you can see from the photo below, conditions were a little strange and there were distinct color bands in the water. I am not sure exactly what caused them, but perhaps it was the angle of the sunlight or the way the wind was moving the water. Whatever the case, it made for a pretty distinctive color change in the top third of this image that almost looks artificial.
© Michael Q. Powell. All rights reserved.
Mike Powell 
I often use online experts on various Facebook sites. Mostly so I read watch them argue .. Greater … Lessor! ‘Is too!” , Is not!”
The difference in the colour of the water is probably because the duck did a wee.
I too am amused when experts have differences of views. Identification is an inexact science and there are so many variables including age, gender, season, and lighting.
That’s a difficult one to separate, the only sure way is the extent of white on the secondaries when seen in flight.
Wow. The more I get into bird identification, the more complicated it seems to get. 🙂 Now I see why “experts” get into such heated discussions.
You should have read some of the discussions I used to follow on internet forums! Every feather detail argued over it sometimes got quite personal, good entertainment though, it made me smile 🙂
Indeed. It’s interesting to encounter experienced birders when I am out and about. Some of them have haughty, know-it-all demeanors and don’t what to deal with neophytes like me. Others are really helpful and more than willing to lend a hand in identifying what may turn out to be common species to them (but not to me).
I’ve seen color differences like that happen in rivers too, but I can’t explain why it happens. I have learned that if you want a river to look blue in a photo you should have the sun behind you.