Click on picture(s) for a larger view.
Solution by Tony Leukering
This week's quiz bird seems to be perched on rip rap, and since there seems to be water behind it, we might surmise that the bird is on a jetty. Of course, that assumption may or may not help us with the bird's ID; it might even send us astray. Regardless, since we can see at least one of the bird's hind toes and it is not elevated, we can rule out any shorebird. In fact, our bird appears to have a stout and short bill, dark above and yellowish below. Those features, also, rule out shorebirds, as do its short, pink legs.
The short and stout bill might send us to the back of the field guide where reside most such ABA-area birds. The plain and dull underparts, in combination with the pink legs, rule out all of the finches. The brown crown and those pink legs might then send us searching among the Emberizidae (the New World sparrows and similar things), but that plain and dingy breast doesn't fit too many options there. The brown towhees are, well, too brown, and the beastie just looks off for it to be any of the plain-breasted sparrows, perhaps because of those blackish bits on the chin and throat. Ah, that lovely, Canadian breeding endemic sparrow, Harris's, has black on the chin and throat, but it should have either a lot more black in that area (adults), or less (immatures), and, if less, ought to have some black spotting/streaking on the upper sides, which it lacks. Even though, to experienced birders, it might seem unlikely, I have seen multiple beginning birders identify those brown birds with black on chin and throat nesting in the eaves of their houses as Harris's Sparrows. That may be because they get to the New World sparrows in the field guide, find Harris's Sparrow, and stop looking. Thus, they don't find, at the very back of the book, that introduced sparrow from the Old World that also sports black chin and throat (and upper breast). While our bird does not sport much of the black typical of a male House Sparrow, we can see the rough outline of that black and be happy with that ID. What we may not know, though, is that male House Sparrows molt in new feathers on the chin, throat, and upper breast in late summer/fall (along with all of their other feathers) that have thin to wide pale fringes that obscure the black throat patch. As those feathers wear through the fall and winter, the black becomes more and more evident.
Those that studied the quiz bird more closely will have noticed that the crown looks at least partly brown, not entirely gray, and that there does not appear to be any black in front of the eyes. Ah, close scrutiny is always good when obtainable. When male House Sparrows grow their juvenal (=first basic) plumage in the nest, they grow female-like plumage. However, once fledged for a bit, they initiate their preformative molt and bring in obviously male plumage. With these facts, we can safely surmise that our quiz bird is an immature male House Sparrow somewhere in the process of replacing its juvenal plumage in its first fall, when I took the picture at Avalon, Cape May Co., NJ, on 7 October 2008. I have included, below, an enlarged crop of our quiz bird's upper body in which one can see the mix of dull, even pale, brown and gray feathering in the crown; the former being juvenal feathering, the latter adult. Amazingly, the location of the photograph was guessed by one respondent, Sean Fitzgerald. Of course, he had an unfair advantage, having spent an entire fall standing by this jetty counting the immense southward migration of waterbirds there, oddly enough, in 2008! Finally, at least as this quiz is concerned, Peter Wilkinson correctly sussed the bird's plumage and which molt it was conducting.
Now that we're a bit over halfway through the quarter's competition, Richard Witters finds himself alone atop the leader board with a perfect 7-of-7 score; seven others are on his heels with 6 correct responses. As for the annual competition, Ben Coulter (30 correct responses) has a one-correct-response lead on Robert McNab.
Incorrect species provided as answers:
none -- excellent!
Congratulations to the 21 of 21 getting the quiz correct:
Logan Kahle
Tyler Bell
Ben Coulter
Jeff Witters
Sean Fitzgerald
Margaret Smith
Nick Komar
Richard Jeffers
Chris Witt
Bryan Guarente
Larry Griffin
Al Guarente
Jim Nelson
Robert McNab
Su Snyder
Peter Wilkinson
Margie Joy
Pam Myers
Sean Walters
William von Herff
Joe Bens
Answer: House Sparrow
Monday, August 13, 2012
Monday, August 6, 2012
Quiz #461 (2012-3-06) Solution
Click on picture(s) for a larger view.
Solution by William von Herff and Tony Leukering
It was obvious to respondents that this week's quiz bird was a juvenile accipiter, and as is often the case with this genus, answers ran the gamut of possibilities. Quiz newcomer William von Herff provided an excellent analysis of the bird, so I'll start with his take and finish up with some minor additional notes. William?
"Ah, a perching accipiter! And a headless one at that! Oh joy! Anyway, you can get to accipiter because of the slim size, the streaks on the underside, and the barred tail. As well, the streaks mean that it's a juvenile.
"So, now we have to differentiate the three accipiters. Well, it's a juvenile, and you can notice that it has what appears to be a clean vent and undertail coverts. Northern Goshawk would have scattered teardrop-shaped splotches on the vent and undertail coverts and a much more broken and scattered under tail pattern, compared to that of the quiz bird.
"So, on to the Sharpie/Cooper's duo. Normally, we could just look at the head structure from this close up, but this bird is hiding its head shape, so we have to figure it out using other clues. So, let's look over some key ID points. The most well-known juvenile accipiter separator is the streaking: Cooper's has thin streaks that fade away around the belly area, while Sharpie has thicker streaks that go farther down. The quiz bird has thin streaks that fade away at the belly area, so this points to Cooper's. The trait is highly variable, though, so I'll give Cooper's 0.75 points (Sharpie: 0 Cooper's: 0.75). The second feature is shape: Cooper's has a very barrel-shaped chest, while Sharpie has a body shape that gets thinner as it goes down. The quiz bird, while it is at an awkward angle, looks very barrel-shaped. (Sharpie: 0 Cooper's: 1.75). Third of all, leg thickness: Cooper's have fairly thick legs, while Sharpies have pencil-thin legs. This bird seems to have thicker legs, so I'd give another point to Cooper's. (Sharpie: 0 Cooper's: 2.75). Next, there's the terminal band: This is very variable, so whichever gets this one, gets only a half-point. Cooper's has a fairly wide terminal band, while Sharpie has an extremely thin terminal band. The quiz bird seems to have a wide terminal band, so Cooper's gets a half-point (Sharpie: 0 Cooper's: 3.25). Then, there's the tail length: This is a very awkward angle, so I'm going to compare it to the length of the wing. On Sharpie, the wingtip ends at the end of the second band from the body, while in Cooper's, it ends at the very start of that band. In this bird, the wing ends at the start of that band, so another point for Cooper's. (Sharpie: 0 Cooper's: 4.25). Finally, tail shape: Cooper's tends to have a rounded tail, while Sharpie has a straight tail tip with two sharp corners. This bird seems to have a tail leaning more toward Sharpie, so a point for Sharpie. (Final score: Sharpie: 1 Cooper's: 4.25). Now, this duo has plenty of variation in every single aspect that I just mentioned, so that's why I thought it would be better to tally up the field marks, instead of doing elimination ID."
Thanks, William! Some other points that I wished to make on this one are that juvenile Northern Goshawk have very thin white bands bordering the dark tail bands that contrast paler both with the obviously dark bands, but also with the wide pale bands. My last comment is that I would probably have given Cooper's the whole point for tail shape because, though the tail is mostly squared-off, we can see the outermost right rectrix (it is misplaced to the middle of the tail) and it is obviously shorter and lacking a distinct corner at the outer edge of the tip (instead, the outer part of the tip is quite rounded). This is a feature that is diagnostic in differentiating Cooper's Hawk from Sharp-shinned Hawk. Steve Mlodinow took this picture of a juvenile Cooper's Hawk at the Shillapoo Wildlife Area, Douglas Co., Washington, in January 2011.
Incorrect species provided as answers:
Sharp-shinned Hawk - 2
Northern Goshawk - 1
Congratulations to the 17 of 20 respondents getting the quiz correct:
Tyler Bell
Al Guarente
Logan Kahle
Ben Coulter
George Cresswell
Su Snyder
Richard Jeffers
William von Herff
Bryan Guarente
Robert McNab
Margaret Smith
Josh Yoder
Peter Wilkinson
Nick Komar
Pam Myers
Joe Bens
Sean Walters
Answer: Cooper's Hawk
Solution by William von Herff and Tony Leukering
It was obvious to respondents that this week's quiz bird was a juvenile accipiter, and as is often the case with this genus, answers ran the gamut of possibilities. Quiz newcomer William von Herff provided an excellent analysis of the bird, so I'll start with his take and finish up with some minor additional notes. William?
"Ah, a perching accipiter! And a headless one at that! Oh joy! Anyway, you can get to accipiter because of the slim size, the streaks on the underside, and the barred tail. As well, the streaks mean that it's a juvenile.
"So, now we have to differentiate the three accipiters. Well, it's a juvenile, and you can notice that it has what appears to be a clean vent and undertail coverts. Northern Goshawk would have scattered teardrop-shaped splotches on the vent and undertail coverts and a much more broken and scattered under tail pattern, compared to that of the quiz bird.
"So, on to the Sharpie/Cooper's duo. Normally, we could just look at the head structure from this close up, but this bird is hiding its head shape, so we have to figure it out using other clues. So, let's look over some key ID points. The most well-known juvenile accipiter separator is the streaking: Cooper's has thin streaks that fade away around the belly area, while Sharpie has thicker streaks that go farther down. The quiz bird has thin streaks that fade away at the belly area, so this points to Cooper's. The trait is highly variable, though, so I'll give Cooper's 0.75 points (Sharpie: 0 Cooper's: 0.75). The second feature is shape: Cooper's has a very barrel-shaped chest, while Sharpie has a body shape that gets thinner as it goes down. The quiz bird, while it is at an awkward angle, looks very barrel-shaped. (Sharpie: 0 Cooper's: 1.75). Third of all, leg thickness: Cooper's have fairly thick legs, while Sharpies have pencil-thin legs. This bird seems to have thicker legs, so I'd give another point to Cooper's. (Sharpie: 0 Cooper's: 2.75). Next, there's the terminal band: This is very variable, so whichever gets this one, gets only a half-point. Cooper's has a fairly wide terminal band, while Sharpie has an extremely thin terminal band. The quiz bird seems to have a wide terminal band, so Cooper's gets a half-point (Sharpie: 0 Cooper's: 3.25). Then, there's the tail length: This is a very awkward angle, so I'm going to compare it to the length of the wing. On Sharpie, the wingtip ends at the end of the second band from the body, while in Cooper's, it ends at the very start of that band. In this bird, the wing ends at the start of that band, so another point for Cooper's. (Sharpie: 0 Cooper's: 4.25). Finally, tail shape: Cooper's tends to have a rounded tail, while Sharpie has a straight tail tip with two sharp corners. This bird seems to have a tail leaning more toward Sharpie, so a point for Sharpie. (Final score: Sharpie: 1 Cooper's: 4.25). Now, this duo has plenty of variation in every single aspect that I just mentioned, so that's why I thought it would be better to tally up the field marks, instead of doing elimination ID."
Thanks, William! Some other points that I wished to make on this one are that juvenile Northern Goshawk have very thin white bands bordering the dark tail bands that contrast paler both with the obviously dark bands, but also with the wide pale bands. My last comment is that I would probably have given Cooper's the whole point for tail shape because, though the tail is mostly squared-off, we can see the outermost right rectrix (it is misplaced to the middle of the tail) and it is obviously shorter and lacking a distinct corner at the outer edge of the tip (instead, the outer part of the tip is quite rounded). This is a feature that is diagnostic in differentiating Cooper's Hawk from Sharp-shinned Hawk. Steve Mlodinow took this picture of a juvenile Cooper's Hawk at the Shillapoo Wildlife Area, Douglas Co., Washington, in January 2011.
Incorrect species provided as answers:
Sharp-shinned Hawk - 2
Northern Goshawk - 1
Congratulations to the 17 of 20 respondents getting the quiz correct:
Tyler Bell
Al Guarente
Logan Kahle
Ben Coulter
George Cresswell
Su Snyder
Richard Jeffers
William von Herff
Bryan Guarente
Robert McNab
Margaret Smith
Josh Yoder
Peter Wilkinson
Nick Komar
Pam Myers
Joe Bens
Sean Walters
Answer: Cooper's Hawk
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