Quiz #383 (2011-1-04) Solution

Click on picture(s) for a larger view.

Answer by Tony Leukering

This week's quiz photo included a large, well-lit image of an obvious cormorant. What is wrong with me? Actually, despite the high-quality of the cormorant's image, this photo has two ways to trip up respondents, with both of those coming into play this week.

The first tricky bit is determining which species of cormorant of the two possibilities, Neotropic and Double-crested, is represented by our focal bird. You see, it's got something of a mix of characters, sporting both a bright orange supraloral stripe (a typical Double-crested feature) and a white edge to the posterior of the gular area (a typical Neotropic character). I noted in an article in Colorado Birds that some Neotropic Cormorants have some orange in the supraloral area, so the presence of orange there is not a sure indicator of an ID as Double-crested, though it is a very helpful ID feature. Our bird's orange supraloral seems too extensive and too obvious to be that of the odd Neotrop.

As noted in a previous Mr. Bill quiz (#363), young Double-cresteds can show a white rear border to the gular area, but that the shape differs between the two species. Neotropic Cormorant has the rear border of the gular area angled forward both above and below the gape, creating an angle of less than 90 degrees. Double-crested, however, has the border below the gape nearly vertical, creating an angle greater than 90 degrees. This week's cormorant has that larger angle.

Some might be thinking evil 'hybrid' thoughts, but the various size and shape characters apparent on this cormorant all point to an ID of Double-crested: the large (both long and thick) bill, the large head, and the short tail.

Now, for the second tricky bit. Note that when writing (above) about the focal bird of this quiz, that I never called it "the quiz bird." That is because there are two birds -- well, a bird and a half -- in the picture, and both are certainly identifiable. The second bird is that swimming duck, with white tail, black butt, orange legs, gray tertials, white belly, and curled black uppertail coverts -- an obvious male Mallard.

Finally, the age of the cormorant: though some respondents called this bird a juvenile, it is older than that, as evidenced by the mix of blackish and brown feathers on the underparts and the complete lack of any real whitish color there. I suspect that this is a second-cycle bird (about 1.5 years old), but I know that I took the picture at Prospect Lake, Wheatridge Greenbelt, Jefferson Co., CO, on 6 November 2006, a time of year when juvenile Double-crested Cormorants would still sport lots of whitish plumage on the underparts.

Eight respondents provided only one species in their answers, six of those getting the correct species of cormorant, though one of those omitted capitalization of the 'cormorant.' Additionally, one correct respondent neglected to capitalize 'Mallard,' so that answer was precluded from being correct for the competition. Finally, multiple respondents included a guess as to the age of one of the birds directly with the species name; since those age estimations were incorrect, the answers were considered incorrect (though these respondents also provided only one species in their answers) -- PLEASE READ THE RULES.

Seven players are tied with perfect scores (4 of 4) at this point, about a third the way through the quarter's competition.

Incorrect species provided as answers:
Neotropic Cormorant - 3

Congratulations to the 18 of 28 getting the quiz correct:
Tyler Bell
Gary Koehn
Pam Myers
Bryan Guarente
Christopher Hinkle
Nick Komar
Christian Nunes
George Cresswell
Ali Iyoob
Margie Joy
Adrian Hinkle
Matt Bristol
Marcel Such
Joel Such
Peter Wilkinson
Tucker Lutter
Chishun Kwong
Nick Moore

Answer: Mallard, Double-crested Cormorant

Quiz #382 (2011-1-03) Solution

No ABA code 3 species (or rarer) in picture

Click on picture(s) for a larger view.

Answer by Marcel and Joel Such and Tony Leukering

The brothers Such provided good solutions, so I'm running with 'em. I find the slightly different tacks they took to get the correct solution interesting and beneficial, particularly as they cover slightly different bases and do my job for me, and well. The first responding of them this week was Marcel, so take it away!

"To start off this quiz, we should immediately note that there are nothing but gulls in the photo, and with the hint that 'No ABA code 3 species (or rarer) in picture,' we can directly limit ourselves to just 19 species. As with the last quiz, we’ll check to see how many species are present. All of the birds, minus the bird in the immediate foreground of the photo, all share distinctive black “ear-muffs,” thin black bill, and tiny white tips on their otherwise black primaries, so I feel confident that these are all of one species. The closest bird, however, is obviously different, being distinctly larger, with a dark gray back; partial dark hood; and thick, slightly drooping, dark bill.

"For the species-specific identification, let us start with the smaller, more abundant, gulls. Of the 19 sub-code 3 species, only three species have the obvious dark ear-muffs, Black-legged Kittiwake, Red-legged Kittiwake, and Bonaparte’s Gull. Of these, only one species has a thin, black bill, Bonaparte’s. The kittiwakes all have thicker, shorter bills of a bright yellow hue.

"For the second species, only three options, Franklin’s, Laughing, and Sabine’s, have the distinctive dark partial hood shown by our bird. From here, Sabine’s can be quickly eliminated because of its comparatively shorter, thinner bill, with a distinct yellow tip. Franklin’s can also be eliminated by its thinner, straighter bill and its white nape (our bird’s is gray). This leaves us with Laughing Gull, which matches our bird exactly."

And now for Joel:

"Comparing all the birds in this photo, it looks like there are two species, obviously gulls. There are six small hooded gulls and one medium-sized hooded gull in winter [basic or formative, depending upon age] plumage.

"The small hooded gulls: All the gulls except for the bigger browner gull in front are small hooded gulls. Field marks on these non-breeding-plumaged birds are dark ear spot; thin, black bill; somewhat-light gray back; and dark primaries. They cannot be Little Gulls, due to the lack of a dark cap. Black-headed Gull can be eliminated, as they lack the heavier red or orange bill. Bonaparte’s Gull, on the other hand, is a perfect fit, matching all the other field marks that are present on the six small hooded gulls in the quiz photo. Other considered birds are both Kittiwakes, which don’t have the right bill or the correct head pattern.

"The medium-sized hooded gull: The gull in the front is obviously of a different species than all the others gulls, being either a Franklin’s Gull or a Laughing Gull. The brown wings and gray hindneck with a dull half hood make it a first-winter bird. It’s not a Franklin’s Gull, which has a whitish hindneck and a more distinctive hood, leaving Laughing Gull as our winner, with its rather heavy, long, slightly drooped dark bill; white forehead and throat; dark auriculars and neck; and brownish wings."

Thanks, guys!

Because they weren't quite specific enough about a couple bits, I'll finish things up. Black-legged Kittiwakes as juveniles have black bills, but in that plumage they also sport that whacking big nuchal collar. While Red-legged Kittiwakes lack that collar as juvs, they also have very tiny bills and very large eyes (relative to head size), which our quiz birds lack. I believe that Joel is right and the Laughing Gull is a first-winter (in formative plumage), but the Bonaparte's are a mix of two ages (readily told by the black in the wing coverts), with two adults, three first-winters, and one of undetermined age present.

I took this picture of six Bonaparte's Gulls and one Laughing Gull off Delaware on 23 November 2010. They were part of a HUGE feeding frenzy including some 1500-2000 Bonaparte's Gulls, 300 Laughing Gulls, 30+ Black-legged Kittiwakes, 20+ Great Shearwaters, a few Manx Shearwaters, and 9+ Parasitic Jaegers (with a few big gulls and a smattering of Northern Gannets thrown into the mix, too). The system works like this: It starts with a big school of baitfish (e.g., Sand Eels [Ammodytes sp.] or Anchovies; this time, Sand Eels, I think -- "Rock me, Ammodytes!") and the big schooling predatory fish, in this case Bluefish and Striped Bass, attack them from below, forcing them to the water's surface. At this point, the gulls and shearwaters can get 'em and start gorging. The final bit is the jaegers pirating the gulls' and shearwaters' free lunches from them.

Two of the three respondents providing only one species in their answers got that one species correct (Bonaparte's).

Incorrect species provided as answers:
Sabine's Gull - 1
Franklin's Gull - 2
Black-legged Kittiwake - 2

Congratulations to the 20 of 26 getting the quiz correct:
Brandon Percival
Christian Nunes
Al Guarente
Pam Myers
Ira Sanders
Tammy Sanders
Chuck Carlson
Ben Coulter
Marcel Such
Kirk Huffstater
Joel Such
Nick Komar
Tucker Lutter
Margie Joy
Matt Bristol
Christopher Hinkle
Adrian Hinkle
Joe Bens
Chishun Kwong
Bryan Guarente

Answer: Bonaparte's Gull, Laughing Gull