Monday, January 2, 2012

Quiz #431 (2012-1-01) Solution

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Solution by Tony Leukering

This quiz saw a fairly high response rate -- keep it up! Also, welcome to the four new players that responded this week.

Our quiz bird is flying over our heads and the camera caught it with its wings closed (par for the course). The bill looks thin and short and the bird gives the feel of a small bird. The underparts pattern rules out most options, but I wanted to tackle the tail first -- one of my favorites field marks on which to harp. Recall that from underneath on a folded tail, most of what we see is presented by the outermost rectrix on each side (the r6s). Those feathers are obviously extensively white, but with distinct black corners and with the bases black, but with most -- but not all -- of that black hidden by the undertail coverts. That general pattern fits a fair few species of warblers and little, if anything, else. McCown's Longspur does have a black chest contrasting with white throat and belly in worn basic plumage. However, that species shows an extensive black tip to the tail, the corners of the tail are white, and black does not show at the base of the tail.

The extensive black on the chest and the little bit of yellow on the upper side at the shoulder should take us directly to Yellow-rumped Warbler without passing 'Go' nor collecting $200. While here, we should probably attempt subspecific identification, as the species very well could be split back into Audubon's and Myrtle warblers in the near future (call notes and songs differ, as does migration timing in the two forms). The extensively white throat with the white extending up behind the auriculars is an excellent indicator of Myrtle Warbler. While some Audubon's Warblers lack yellow on the throat, those are usually immature females in fall and winter, rather than what we have here, which is an adult male in high plumage. We should probably also check for hybrid characters, with the single best being a mix of color in the throat, but the extension of our bird's white behind the auriculars (the "ear surround") is another character that Audubon's does not sport. I took this picture of an adult male "Myrtle" Yellow-rumped Warbler at Cape May Point, Cape May Co., NJ, in late April 2011.

Two responses were considered incorrect for the competition due to nomenclatural issues; one included "Myrtle" directly in the species name ("Yellow-rumped Myrtle Warbler") and one capitalized "rumped" (see the rules).

Incorrect species provided as answers:
McCown's Longspur - 2

Congratulations to the 29 of 31 getting the quiz correct:
Tyler Bell
Robert McNab
Margaret Smith
Josh Parks
Pam Myers
Thomas Hall
Laura Osborn
Megan Miller
Aaron Brees
Jeff Witters
Marcel Such
Kirk Huffstater
Rudi Nuissl
Rob Fowler
Bruce Mast
Peter Wilkinson
Jim Kopitzke
Su Snyder
George Cresswell
Christopher Hinkle
Ben Coulter
Diane Porter
Margie Joy
Ben Griffith
Joel Such
Sean Walters
Devich Farbotnik
Bryan Guarente
Chishun Kwong

Answer: Yellow-rumped Warbler