Monday, December 12, 2011
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Solution by Tony Leukering
This one was a toughie. Had I not known that previously, the diversity of species in answers this week would have driven the point home, as seven species of four families were submitted in response to the quiz. All species provided as answers share the quiz bird's general features of brown with dark-centered feathers on the wing and streaks on the flanks; most also sport white outer webs to the outermost rectrices.
Our quiz bird's tail rules out a couple of the submitted options: Sky Lark's tail has the middle feathers on each side blackish contrasting with paler central tail feathers and Le Conte's Sparrow's tail is shorter, spikier, and lacks pale outer webs to the r6s. Savannah Sparrow is quite similar to the appearance of our quiz bird, but has buff or cream sides to the tail, not white.
The bird's right wing provides most of the best clues as to its identity. It lacks rufous lesser coverts, a distinctive feature of Vesper Sparrow. Le Conte's and Savannah sparrows both have a darker, more-even-colored wing, which results in the median and greater coverts not providing such strong contrast, and Le Conte's lacks our bird's distinct wing bars created by extensive buff tips to the black-centered greater and median coverts. Lapland Longspur has even darker wings, such that the rufous greater coverts contrast paler. Sky Lark's wings are an even-colored grayish-brown lacking in any obvious contrast. Red-throated Pipit has white wing bars on a relatively non-contrasting dark wing and with the greater coverts, if anything, paler than the rest of the wing.
The quiz bird's back provides the final clue: there are wide, buffy braces (long, contrastingly pale streaks) that are a feature of fairly few bird species. All of the above features, in combination, rule out all but the correct answer. Another picture of the same individual is provided below to prove the point. Tom Johnson took these pictures of a Baird's Sparrow flying away at Willcox, Cochise Co., AZ, on 4 May 2011.
One of the incorrect answers, even if correct, would have been precluded from being correct for the competition due to nomenclatural issues.
Incorrect species provided as answers:
Vesper Sparrow - 5
Lapland Longspur - 4
Red-throated Pipit - 1
Savannah Sparrow - 2
"Eurasian Skylark" - 1
Le Conte's Sparrow - 1
Congratulations to the 4 of 18 getting the quiz correct:
Answer: Baird's Sparrow