Monday, July 18, 2011

Quiz #408 (2011-3-03) Solution

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Solution by Tony Leukering

This week's quiz bird has both colors, black and white (apologies to "The Blues Brothers"). While there is a good variety of birds that have black or blackish bodies and black-and-white wings, the precise distribution of the black and the white on the underside of the wing is the critical factor in this quiz.

What we can see of the torso of the quiz bird is entirely black, as is the tail; the wing linings are entirely white. Additionally, no feet are visible. Thus, while not necessarily definitive, California Condor (and its big, pale feet) is probably ruled out. In fact, the only two options with these considerations are the two species most-frequently provided as answers by respondents: Muscovy Duck and Pileated Woodpecker. However, let me point out a feature that one of these two camps did not note: the remiges are only MOSTLY black -- please note the adverb!

The brighter white bits on the bird's right wing are the bases of the inner primaries, which, if we could see such in this picture, would show from above as a basal-primary patch of white. The whiteness is due to the fact that there are no other feathers betweeen that white and the sun, while the wing lining white is duller and grayer because the sun is not shining through that white due to the opacity of the intervening bits (skin, muscle, topside feathers). The brightness of the white on the left wing is due to the fact that it is facing the sun and being directly lit.

So, the upshot is that this basal-primary patch is something that the duck does not sport; nor does California Condor, which shows a basal-secondary patch of white. Steve Mlodinow took this picture of a Pileated Woodpecker in February 2011 in Monroe, Snohomish Co., WA.

Incorrect species provided as answers:
Swallow-tailed Kite - 1
Muscovy Duck - 4
California Condor - 1

Congratulations to the 12 of 19 getting the quiz correct:
Tyler Bell
Christian Nunes
Su Snyder
Adrian Hinkle
Al Guarente
Kirk Huffstater
Robert McNab
Christopher Hinkle
Diane Porter
Nick Komar
Marcel Such
Joel Such

Answer: Pileated Woodpecker