Monday, November 19, 2012
Quiz #475 (2012-4-07) Solution
Solution by Tony Leukering
Ah, another tricky swallow/swift thing. The upperparts are unrelieved brown. While we cannot see much of the underparts at all, the throat is quite pale. First, we'll tackle the swift/swallow dichotomy. The wide-based wings with a fairly wide arm (part of wing from base to wrist) is wrong for swifts, particularly Chimney and Vaux's, which have very narrow-based wings and short arms.
Once we're among the swallows, we can quickly rule out all but the "brown" swallows: Northern Rough-winged, Tree, and Bank (this bird does not have the heft of a martin, such as Brown-chested). Unfortunately, we cannot see the tail shape well, but there's at least the suggestion of a notch or fork, though I'd be leery of depending upon that mark from this tricky view, so we'll keep Northern Rough-winged in the mix for now. The striking aspects of the bird to me are the very dark wings and the rump being the palest part of the upperparts plumage. Northern Rough-winged Swallow is typically unicolored -- or very nearly so -- above, particularly with brown flight feathers, not blackish ones. Tree Swallow shows an obvious indentation of whitish behind the wing on the flank that is lacking in our quiz bird. Other features supporting the ID as Bank Swallow include the very narrowly-pointed wings, narrow back end of the body, and pale fringes to the uppertail coverts. In my experience, from above, Bank Swallow's color is palest on the rump and gradually gets darker in all directions. I have another picture of this individual Bank Swallow on my Flickr site, which I took at Big Johnson Res., El Paso Co., CO, on 1 June 2011.
Incorrect species provided as answers:
Northern Rough-winged Swallow - 11
Chimney Swift - 3
Tree Swallow - 3
Purple Martin - 1
Congratulations to the 1 of 20 getting the quiz correct:
Answer: Bank Swallow