Monday, January 11, 2010

Quiz #331 (2010-1-02) Answer

Click the picture for a larger view.

Answer by Tony Leukering

After finally biting the bullet and telling myself that I would just have to start from scratch with the scoring spreadsheet, the original of which I lost when my thumb drive gave up the ghost (not an easy thing!), I'm finally getting around to catching up on answers for the Quiz. I apologize to all for the extreme delay in getting this done. I mean, it's now 20 Feb, and the I've only provided one of this year's answers so far! It will take a while to get caught up, but hopefully you'll hang in there. I'm particularly annoyed that I lost the files when I did, as I'd just completed writing an incredibly long answer for this quiz photo -- probably the longest of my tenure. Ah, well.

All respondents noted that this week's quiz presents a bunch of ducks, with some really obvious male Mallards among 'em. Starting there, note that virtually all the rest of the birds are similar in size and structure, which tells us that they should also be large dabblers. Note that the male Mallards all have dark heads (one might even be able to imagine some greenish aspect there), dark chests, pale bellies that contrast strongly with the chest, and white or whitish wing linings. There are six male Mallards, including four of the upper-left five birds.

Knowing that the birds are large dabblers, should enable us to eliminate nearly all other options, except for the two species of Mallard-like dark dabblers (American Black and Mottled), Gadwall, the two wigeons, and the two Northerns, pintail and shoveler. I want to head next to the fairly different birds present, the seven dark things -- three about in the middle of the flock, one almost on the bottom edge of the picture, the bird two birds behind (and above) the bottom one, and the two right-most birds. These birds show heads paler than their chests, but not as pale nor as creamy-colored as is typical for Mottled Duck. The Mexican Duck -- currently considered a subspecies of Mallard, but which has been shown to be more closely related to the other dark dabblers than it is to Mallard -- would not be quite so dark, and would/should show even paler markings on the sides and flanks. These birds are American Black Ducks.

The above means that we've identified 13 of the 18 birds and that we're going to have to deal with brown female things. I know that a fair number of birders like to duck the issue (sorry, I couldn't stop myself) of identifying brown ducks, but they're really not that hard and with so many male Mallards present, it would probably behoove us to look for females. Looking down at the bottom row, check out the left-most bird. Most aspects visible on the male Mallards are visible also on this bird: dark head and chest contrasting with paler belly and whitish wing linings. This is perfect for a female Mallard, and the bird's shape is even identical to that of the male Mallard behind it. Other similar-appearing birds can be found above and right behind the first one, three and five birds back in the same row. These birds all appear quite similar and all definitely have very pale wing linings. Of course, Gadwall, American Wigeon, and Northern Shoveler females also sport pale or white wing linings, but there are no huge bills present and Gadwall and American Wigeon have longer, more pointed tails. And, of course, female Eurasian Wigeon also exhibits a longer, more pointy tail, but they have gray wing linings. Northern Pintail females also have pointy rear ends and darker wing linings. And, well, look at that, would ya, that top-most bird has brown wing linings and a long, attenuated rear end. Yup, there's the hidden bird, right out in the open, where I like 'em! Also note that bird's slimmer build and narrower, longer wings. It even looks a bit smaller overall; again, absolutely perfect for female Northern Pintail.

I took this picture just north of Cape May, Cape May Co., NJ, on 30 November 2009. There were a lot of other birders present at the site, but they were looking in the opposite direction at some weird, pale gull thing. I think that they were saying something like "Ivory Gull," whatever that is! I provide another version of this picture, below, with indications of identification.

Seven respondents provided no incorrect species, but did not provide enough correct ones. One respondent's answer was precluded from being correct for the competition due to not providing the 'American' at the head of 'American Black Duck.' Finally, two answers were received after the deadline.

Incorrect species provided as answers:
Steller's Eider - 1
Cinnamon Teal - 1
Eurasian Wigeon - 1
Gadwall - 2
Green-winged Teal - 1

Congratulations to the 12 of 29 getting the quiz correct:
Tyler Bell
Chuck Carlson
Kevin Kerr
Mark Dettling
Peter Wilkinson
Al Guarente
Marcel Such
Joel Such
Joe Bens
Aaron Brees
Bryan Guarente
Andrea Smith-Guarente

Answer: American Black Duck, Mallard, Northern Pintail