Monday, March 15, 2010

Quiz #340 (2010-1-11) Answer

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Answer by Tony Leukering

Wow, the third duck in a row! Spring, anyone?

This week's duck is not a diving duck, as the strongly-marked body feathers suggest. Among dabbling ducks, bill size and color, head color and pattern, tertials color, tail color, and leg color are all very useful features and all of them more or less visible in the picture. Obviously, I'm losing my touch if that's true!

I am starting with bill color, a most useful feature. Our bird's bill looks entirely dark except for a thin bit of orange along the cutting edge. These facts rule out females of all but the four teal and Northern Pintail and males of all species but the four teal and Gadwall. The thickness and apparent width of the bill rule out any of the above non-teal possibilities.

At this point, we might consider trying to age/sex the bird. One of the easiest ways to age waterfowl is to check out the tail, as youngsters' tails tend to wear to whitish much more readily than those of adults. This is useful because, except for Mallard and Northern Shoveler, none of our ABA-area dabblers should sport much white in the tail. Our bird's tail seems to have a whitish fringe, which just might suggest that it's not a full adult, though I don't know that I'd want to place a large monetary bet on that.

As to sex, it looks like a female, but might it be a male in alternate ("eclipse") plumage? In general, male dabblers in alternate can be quite similar in appearance to that of females, but with less contrast of the colors within individual feathers (in Gadwall, the Mallard group, and teal) if they don't simply look like 'odd' males (in wigeon and the two Northerns -- shoveler and pintail). Our bird certainly doesn't look like an odd male, but we already know that it's a teal. Looking closely at, particularly, the feathers of the sides and flanks, we can see that they are brown-centered with obvious whitish fringes. The tertials are similar in that respect, so our bird is almost certainly not a male. Throwing in the picture's date -- which was not given -- of 9 April 2006 (at Chico Basin Ranch, Pueblo Co., CO, by yours truly), we can be absolutly certain that it's not a male, as any male teal in the ABA area should be in basic plumage at that point.

Knowing the sex, now, should enable us to get on with the species ID. We can just barely see a hint of leg color in the water and it looks yellow or orange, which rules out Green-winged Teal. Of course, we have other ways to rule that species out: bill size, lack of triangular cream or yellow patch below tail, extensive white fringing to side feathers, and the white area between eye and bill, among others. Garganey can be eliminated by our bird's complete lack of a second facial stripe, the one originating at the gape in Garganey and that the eyeline doesn't continue through the eye to the bill; again, among other features.

That leaves us with the Blue-winged/Cinnamon duo that, in my opinion, is considered by too many to be too difficult to ID in the field. I've dealt with that duo previously in Mr. Bill Mystery Quiz #232. As there, our bird's strong eyeline, white in front of the eye, cold aspect to the plumage color, and the strong contrast within each side feather point us right at Blue-winged Teal and well away from Cinnamon Teal. Of course, had you seen the bird in the field, you might also have noticed the male behind it!

One respondent's answer was precluded from being correct for the competition as it incorrectly capitalized the 'w.' Another's was precluded for including incorrect details of age/sex directly in the answer (see rules).

Incorrect species provided as answers:
Garganey - 1

Congratulations to the 24 of 25 getting the quiz correct:
William Velmala
Al Guarente
Thomas Hall
Joel Such
Marcel Such
Claire Mix
Matt Bristol
Chuck Carlson
Kirk Huffstater
John Bissell
George Cresswell
Kevin Kerr
Louie Toth
Su Snyder
Tyler Bell
Andrew Dettling
Aaron Brees
Peter Wilkinson
Bryan Guarente
Chishun Kwong
Andrea Smith-Guarente
Chris Warren
Joe Bens
Judi Owens

Answer: Blue-winged Teal