Monday, March 8, 2010

Quiz #339 (2010-1-10) Answer

Click the picture(s) for a larger view.

Answer by Tony Leukering

All respondents got this week's quiz bird to the correct genus, though not all picked the right member of Aythya. However, I'll start by getting us to the correct genus.

Though some might start farther out, I will start with the assumption that the quiz bird is a duck. The bird's behavior -- in the midst of diving from the surface -- suggests that it's a diving duck, though all of the dabblers can dive, they just do not do so all that often. However, our bird's strong pattern of dark head and chest, gray back, gray sides, and white belly are just not matched by an ABA-area dabbling duck. Once among the diving ducks, that same pattern eliminates all ontenders other than the seven ABA members of Aythya, the so-called 'bay ducks.'

We can immediately eliminate the two black-backed species, Tufted and Ring-necked, and concentrate on the others. Head color would be a useful feature here, but the exposure of the picture might make that a bit tricky, so we'll continue from another body part. It doesn't particularly matter whether we start at the back or the sides, either way, we should be able to drive straight to the winning answer (also known as the correct ID). Male Canvasbacks have white backs and sides, not gray, and females don't have black chests, so that species can be ruled out.

The two scaup species are up next. Greater Scaup males in basic ("breeding") plumage always show strongly contrasting white sides with their gray backs (with the gray actually being alternating black and white bands). Lesser Scaup is certainly thought of as having dingier sides than does Greater Scaup, but they also never show such lack of back-sides contrast. As there is no apparent smudgy brown bits on the sides, we can be certain that the bird is not a molting immature male Lesser Scaup, which would have been our best hope for that species. Female scaup are never gray-backed nor gray-sided.

That leaves us with quite a difficult twosome, Redhead vs. Common Pochard, particularly with the front half of the head missing (the part holding all of the best separating characters). If it weren't for the fact that I took the picture (12 May 2006, Belmar Park, Lakewood, Jefferson Co., CO), and if I didn't provide another view of the same individual, below, I couldn't prove that the bird isn't a Common Pochard. I would bet that one or both of our regular European players could tell me, but I don't see anything definitive enough to be certain of the ID from this single picture. And, in fact, when I posted this photo, I was willing to count both species as correct answers. With the additional photo, our quiz bird is most assuredly a Redhead, with it's rounder head and mostly-gray bill with a thin, vague, and paler subterminal band and black tip (vs. the more Canvasback-like profile and more extensively black bill of Common Pochard). Now that we know our bird is a male Redhead, we can look back at the quiz picture and get a suggestion of red on the head, at least on my monitor.

With three quizzes to go in the quarterly competition, Aaron Brees and Al Guarente sit atop the leader board with perfect (10 for 10) scores. They have four others breathing down their necks.

Incorrect species provided as answers:
Canvasback - 3
Lesser Scaup - 5

Congratulations to the 18 of 26 getting the quiz correct:
William Velmala
Matt Bristol
Bryan Guarente
Aaron Brees
Kirk Huffstater
Kevin Kerr
Judi Owens
Claire Mix
Tyler Bell
Al Guarente
Joel Such
Andrew Dettling
Chris Warren
Peter Wilkinson
Thomas Hall
Joe Bens
Marcel Such
Chishun Kwong

Answer: Redhead