Thursday, April 2, 2009

Quiz Bird Answer

Quiz bird revealed, read on to learn its identity.

Quiz Bird - Image 1 A headless passerine: who am I?

I photographed this headless-looking bird on a March 20th trip to the Horseheads Marsh (aka, Holding Point) in Horseheads, NY. Those who guessed correctly narrowed it to one of the "Little Brown Jobs," and nishiki_85 noted the streaked, rusty back and the two white wing-bars, surmising the bird is an American Tree Sparrow.

Quiz Bird - Image 2A little more information here, the rusty cap and a gray face visible.

In addition to tree sparrows there are eight "LBJs" that we might expect in this area at this time of year, some more common than others. Looking carefully you may note the flanks are clean, not streaked, and slightly buffy. This helps eliminate several species: Song, Savannah, Fox, and Vesper Sparrows should all show streaking on the flanks.

Those relatively broad, white wing-bars are helpful, too. They reinforce this bird is not Song, Savannah, Fox nor Vesper, but also eliminate Swamp, White-throated, even White-crowned (I find it wonderfully bizarre those are winter residents at my folks place in Rochester, NY but rare here, 70 miles southeast).

House Sparrows, an honorary LBJ sparrow, do have white in the wings, but a large, single patch rather than two bars.

The only other possible (I wouldn't call it expected, but eBird allows it) sparrow is the Field Sparrow. How to separate these two without seeing the obvious differences, such as face and bill color/pattern? Well, hmmm. First, probability says American Tree Sparrows are much more likely than Field Sparrows, so lean in that direction. Then, wait until it shows its face. Seriously, in looking for differences in the visible parts (back, wings, tail), I'm not sure I could tell.

Gentle readers, how would you tell them apart?

American Tree SparrowNow you can see it all: bicolored bill, gray face with rusty cap and eyeline,
chestnut and black wings with white wing bars, brownish rump.


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