A young birder named Paul sent me a comment on my personal blog about a quiz photo on View from the Cape from February 7, 2011: ". . . Could you please answer a question from the "View from the Cape" blog from February 7, 2011 about the diving duck? How can you tell the difference between greater and lesser scaup when you can't see the wing stripes and shape of the head? Thank you very much! - Paul, age 11."
Here's the photo in question, taken at Turkey Point last February:
The answer, Paul, is if I can't see head shape or wing stripe on a scaup, I can't identify it, and sometimes, although I'm getting better at it, I can't identify individual scaup even if I can see every part of the bird perfectly! I knew this bird was a Greater Scaup because I spent about 20 minutes studying it as I photographed it, and saw the wing stripe extending well out onto the primary feathers when it preened, and got a good fix on the head shape - peak over the eye, sloping rear crown - when it was in a relaxed pose. A question I often ask myself is why, after over 30 years of birding, do I still sometimes have trouble with scaup? The answer is, they are tough to sort out!
All that being said, I would have guessed Greater Scaup on this photo thanks to one minor supporting mark - the thick-looking neck. Thanks for asking, and let us know if you find a favorite way to tell the scaup apart!