Quiz #289 (2009-1-10) Answer

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Answer by Mark Gabriel and Tony Leukering

Mark Gabriel, again, provided cogent reasoning to support his correct answer for this week's quiz, so I'll start with his answer.

"It's interesting to see a photo of birds that seem immediately identifiable, but hard to say why. It reminds me of taking a neophyte out birding and mystifying them by being able to identify distant birds on clues that you, yourself, are unable to put into words, because you have never thought about it. These birds look like starlings, European Starlings, but why?

"All nine birds look the same. We see overall dark birds, brownish or blackish. Their shape is more useful than "traditional" field marks of color or pattern. They seem to be flocking -- loosely. These are rather stocky, clean-cut, compact birds. They have longish, straight, pointed bills and short, square-cut tails. This gives them a pointed "bullet" or "torpedo" shape that is accentuated by wings that are triangular and set in the middle of the body. There is roughly as much bird in front of the wing as behind. There is a variety of flapping going on, including some open-winged glides.

"This combination of shape and the open-winged glides, along with the dark color, long, pointed bill, and the overall dark color all point to European Starlings. Brown-headed Cowbird is longer-tailed and shorter-billed. The triangular-shaped wings and short, stubby tails of these quiz birds rule out the other blackbirds. Meadowlarks would show more color and fatter bodies.

"In life, there is little that looks like flying starlings. I am sometimes struck by waxwings in flight -- that they are reminiscent of starlings. But these birds are long-billed and lack yellow terminal tail bands. Parrots and parakeets also have a flight style that reminds one of starlings, but nothing else here fits for that. These starlings look like they might be in pretty fresh fall/winter plumage, with brownish-golden tones to the upper sides and extensive whitish/gray underneath from the abundant white chevrons on a black ground color."

Thanks, Mark! I really don't have much to add. However, one of the birds, the top bird of the bottom-right three, shows much more rounded wingtips, but that is certainly due to the bird not gliding and with its wings being caught in mid-flap and changing shape preparatory to being pulled in and closed. Finally, I want to note that the easiest species to mistake for European Starlings in the ABA area, at least in my experience, are the two species of waxwings -- they have quite similar shapes. I took the picture of European Starlings on 13 October 2004 in Colorado.

Two respondents provided answers in the plural, thus being precluded from being correct for the competition (see the rules and last week's answer!).

Tallies of incorrect species provided in answers:
Bohemian Waxwing - 3
Cedar Waxwing - 2
Sprague's Pipit - 1
Northern Flicker - 1

The 22 of 29 providing the correct answer:
Brandon Percival
Joel Such
Marcel Such
Szilard Daroczi
Nick Komar
Jessica Brauch
Chris Warren
Tyler Bell
John Bissell
George Cresswell
Andy Dettling
Aaron Brees
Tom Parchman
Peter Wilkinson
Mark Gabriel
Robert McNab
Su Snyder
David Hill
Thomas Hall
Bryan Guarente
Chishun Kwong
Linda Powers

Answer: European Starling

Quiz #288 (2009-1-09) Answer

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Answer by Tony Leukering

Back to gulls! Aaarrgh!

There are four of 'em this time, and they look to be of fairly similar size and build; perhaps there is only one species present -- that would be nice, eh? All birds are gray-mantled, with most having obvious white tips to the outer primaries, which tells us that they're adults in definitive plumage (or very nearly so; see below). Though the lighting could be throwing off our estimation of eye color, the birds whose eyes we can see have dark irides and that, combined with the plumage and the fairly short and thin bills, greatly reduces the options for us. In fact, there are only two that we ought to seriously consider: Mew and Thayer's gulls (Laughing Gull lacks such strong white tips to the outermost primaries.)

If we had other species for direct comparison of size, we should have no probably separating Mew and Thayer's gulls, but we don't have such, so we'll have to figure out some other way to make that determination. A very suggestive feature is that the birds are riding fairly high in the water with their wingtips and rear ends elevated above the horizontal. This is a feature of the smaller gulls; larger gulls having these parts more nearly parallel to the water's surface. Note that I wrote 'suggestive' and not 'definitive.' That is because Thayer's Gulls are fairly small for large gulls and smaller individuals often show a non-parallel upper surface.

But, there is a feature that is definitive illustrated in this picture: the undersides of the far wingtips. This is a feature that is quite helpful in gull ID and the middle two birds are positioned to show the feature at least moderately well. On both birds, what we can see is a large white terminal half of the visible part of the outermost primary (p10) and a black basal half. Thayer's Gull sports a mostly pale underside to p10, with only the outer web being dark, not the basal parts of both inner and outer webs.

I took this picture of four Mew Gulls at the Everett, WA, sewage ponds 6 February 2005. As noted by a couple of respondents, one or more of the birds might be not-quite adults. The dark bits on the a few of the birds' bills might suggest that (or just be typical markings of many basic-plumaged birds). However, note that the center front bird seems to have larger white primary tips than do the back and right-most birds. Such smaller tips provide a strong suggestion that checking the birds more carefully could tell us that the birds are a bit delayed in obtaining definitive plumage and, for these Mew Gulls, would suggest that any such birds are in their 3rd plumage cycle. Most Mew Gulls should have obtained definitive plumage by their 3rd cycle (and be indistinguishable from older birds), but a fairly substantial minority don't quite get there and obtain their first definitive plumage in their 4th cycle. The left-most bird is at such an angle to preclude any definitive assessment of this feature.

One respondent's correct answer was precluded from being correct for the competition as it was submitted in the form of a plural. Please, all, the rules say that the answer must be the accepted name of the species, and those are not in plural form. For the same reason, one incorrect answer would have been precluded had it been correct.


Tallies of incorrect species provided in answers:
Herring Gull - 3
Thayer's Gull - 1
Laughing Gull - 1
Lesser Black-backed Gull - 1


The 22 of 28 providing the correct answer:
Brandon Percival
Nick Komar
Ann McDonald
Andy Dettling
Aaron Brees
Bryan Guarente
Peter Wilkinson
Mark Dettling
Chris Warren
Peter Burke
Thomas Hall
Mark Gabriel
George Cresswell
Tom Parchman
Robert McNab
David Hill
Tyler Bell
Joe Bens
Joel Such
Marcel Such
Chishun Kwong
Victor Germain

Answer: Mew Gull