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New Photo Quiz: July/August 2013 Birding

Quick! Think of some of the notorious species-pairs for ABA Area birders. Chances are, You thought of one or more of the following:

1. Downy and Hairy woodpeckers
2. Alder and Willow flycatchers
3. Western and Semipalmated sandpipers
4. Cooper’s and Sharp-shinned hawks
5. Bay-breasted and Blackpoll warblers (in fall)
6. Sooty and Short-tailed shearwaters
7. Rufous and Allen’s hummingbirds
8. Iceland and Thayer’s gulls
9. Western and Eastern screech-owls
10. Hoary and Common redpolls

I’m not saying you thought of all 10. But at least one, yes? Depending on where you live, how long you’ve been birding, and which field guide you use, you’ve probably been vexed by one or more of the preceding.

We could continue the exercise and come up with a list of the Top 25 confusing species-pairs for North American birders.

I wonder how many of us would name this species-pair:

Chimney and Vaux’s swifts

I think we tend not to ponder this pairing for the simple reason that we can ID the birds by geography alone. Geography is, of course, critical for bird ID. If we see a brown-headed pygmy of a nuthatch in Georgia, we know it’s a Brown-headed Nuthatch; if we see such a bird in Nevada, we know it’s a Pygmy Nuthatch. Range is almost always the best way to separate the closely related but geographically distant Brown-headed and Pygmy nuthatches.

So it is with Chaetura swifts, right? East of the Rockies: Chimney. West of the Rockies: Vaux’s. A Chaetura swift in Philadelphia is a Chimney; a Chaetura in Portland is a Vaux’s. (“Chaetura,” you ask? It’s a genus of swift. Two species–Chimney and Vaux’s–occur in the ABA Area.)

The problem with the ID-by-geography approach is that it’s far from foolproof in the case of North America’s Chaetura swifts. When I moved out West, I was surprised to learn that the common summertime Chaetura in Los Angeles is–wait for it–the Chimney Swift! And birders with the famous 4th edition of Peterson’s Field Guide know that the Vaux’s Swift is very rare but probably regular in Louisiana from fall through spring.

Swifts migrate great distances, and they have tremendously powerful wings. The ID-by-geography approach is usually a safe bet for Brown-headed and Pygmy nuthatches (although the folks in Oklahoma, where both species have occurred, might disagree), but it’s risky with North America’s Chaetura swifts.

Which brings us to the matter of the New Photo Quiz in the July/August 2013 Birding. Below I’ll post the three quiz images. Ordinarily, we tell you the location and date of our quiz images; after all, in most real-life birding situations, you tend to know where you are and what the date is. For this quiz, we’ll tell you that all three images are from spring. But let’s not reveal the locations of these swifts. Let’s see if we can ID them on the basis of what they look like. Remember: This *could* be Los Angeles in May or New Orleans in April!

As usual, I have a request. Please tell us why you think the birds are what you think they are. What are you seeing–field marks, size and shape, behavior, whatever–that has led you to your identification?

Tom Johnson’s official answers will appear in the September/October 2013 Birding. But let’s first see if we can work this out together online.

Here goes:

13-4-16-01 [Quiz Bird A]Quiz Bird A.Photo by (c) Tom Johnson.


13-4-16-02 [Quiz Bird B]Quiz Bird B. Photo by (c) Tom Johnson.


13-4-16-03 [Quiz Bird C]Quiz Bird C.Photo by (c) Tom Johnson.




Update–Oct. 20, 2013.

If you don’t want to see the answers to this quiz, either back up immediately or skip down into the comments. Ready? Here goes . . .










As many of us have already figured out, Quiz Bird A is a Vaux’s Swift, Quiz Bird B is a Chimney Swift, and Quiz Bird C is a Chimney Swift. But here’s a twist: Quiz Birds B and C are the same individual bird.

Tom Johnson’s thorough analysis of these quiz birds appears in the print version of the September/October 2013 Birding, pp. 48-52. There’s a lot of great info in Tom’s article, including a summary of 9 characters for separating the ABA Area’s two Chaetura swifts, an eye-opening look at “Modified Aspect Ratio,” and a dazzling photo salon of incredible close-ups of swifts in flight.

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Ted Floyd

Ted Floyd

Editor, Birding magazine at American Birding Association
Ted Floyd is the Editor of Birding magazine, and he is broadly involved in other programs and initiatives of the ABA. He is the author of more than 100 magazine and journal articles, and has written four recent books, including an ABA title, the ABA Guide to Birds of Colorado. Floyd is a frequent speaker at birding festivals and state ornithological society meetings, and he has served on the boards of several nonprofit organizations. Mainly, he listens to birds at night.
Ted Floyd

Latest posts by Ted Floyd (see all)

  • Ted Floyd

    Ah. Looks like you need to click on the images to make them nice and big–and maybe even identifiable! Bear with me: I’m a WordPress newbie. My first impression, I have to say, is that the switch-over is a wonderful improvement for The ABA Blog. In due course, I may learn how to format images; I may even learn how to italicize “Chaetura” and “Birding”!

    • WordPress makes your life easier. You italicize just like a word processor, command-i on a Mac.

  • Dave Irons

    Hutton’s Vireo vs. Ruby-crowned Kinglet is often a challenge along the West Coast.

    • Ted Floyd

      A masterful effort at evading the question, Dave… 🙂

      (Seriously, though, I agree with you about Hutton’s Vireo vs. Ruby-crowned Kinglet–one of the most surprising pairs of confusing species, given how distantly related they are.)

    • Matthew

      I used to think that they were difficult to separate until I definitively saw a Hutton’s Vireo. Never again….

    • Sterling60

      A funny thing happened during an AOU meeting a few years ago. I saw a poster presented by a US Forest Service researcher who claimed that she didn’t have to hire real birders to do a field project in a SW canyon as she could hire non birding interns to mist net and band birds. She claimed that anyone can properly identify a bird in the hand using a key. Well….her main point was illustrated by a photo of two birds in the hand that were identified as a Dusky and a Hammond’s flycatcher. This was great….two birds that some birders have a difficult time identifying can be identified by anyone. The only problem was that the two birds were both Hutton’s Vireos. so let the Empidonax/Hutton’s Vireo challenge begin!

  • Nate Swick

    If my experience as an eBird reviewer is any indication, House and Purple Finches are near to impossible to differentiate.

  • John Walters

    Living in southern California, I thought I was pretty familiar with Vaux’s Swift, until I had an opportunity several summers ago to spend an hour or so closely observing undoubted Chimney Swifts over a lake in eastern Illinois. Even with excellent views, and with field guide descriptions in hand, I simply could not see the purported differences between Chimney and Vaux’s Swifts. They’re pretty subtle! Based on those field guides, I’d call the top two Vaux’s Swift and the bottom one Chimney Swift, but I wouldn’t be surprised if I’m wrong.

  • Steve Hampton

    Bird C appears darker rumped and longer-winged (at least the bulge on the trailing edge is further out and more pronounced), so I agree the top two are Vaux’s and the last one is Chimney– with a low degree of confidence!

  • Chris Hill

    In order, Vaux’s, Vaux’s, Chimney. I’m just going on paleness of throat and rump, and yes, I realize that in order to make some point about knowing MORE than one field mark, Ted (or Tom) probably included a pale Chimney swift. But I don’t care – I’m sticking with Vaux’s Vaux’s Chimney.

    • Nathaniel Nye

      I’m calling them Vaux’s, Chimney, Chimney. Basing this on structure rather than color… To me the bottom two show flaring inner primaries giving a spatula shape to the wing, which is something I commonly observe in Chimney Swifts but not in Vaux’s.

  • Ted Floyd

    Looks like we have consensus building on Quiz Birds A and C. B is not yet resolved, though. Mind you, consensus is not necessarily the only way to truth and enlightenment.

  • Tristan McKee

    My first impression was the same as Nathaniel Nye’s: the wing shape of B points to a pale Chimney. Bird A stands out as the only obvious Vaux’s by it’s short, triangular, almost starling-like wings. However, foreshortening can exaggerate this impression. Also, B and C are in different stages of a bank, which makes the wing shape different from how we see it most of the time (flapping or gliding). So, it’s a very hard call without my favorite characters–calls and wingbeat–available to us.

    • Sterling60

      I think you got it Tristan

  • Scott Pendleton

    Vaux’s, Chimney, Chimney. Middle based on overall impression, the rump lightness may artifact, and longest upper tail covert extends all the way to spines, note the thin dark line on photo one where the upper tail coverts stop short.

  • Ian McLaren

    These virtually in-the-hand shots permit inspection of a mark noted by Pyle, among others, – extension of the uppertail coverts short of the rect tips in bird A, but to the tips in the other two. Despite its pale rump, B appears to be a CHSW.

  • Averaves

    Yes, A & C seem straightforward as Vaux’s and Chimney, respectively, but B has conflicting characters between coloration that says Vaux’s and structure that says Chimney. Since I’m a structure-bias kind of a guy, I favor calling B a Chimney Swift, even with the caveat that the exact flight action can change the apparent wing shape a bit. I’m trying not to cheat by using the Pyle character that would be impossible to use in the field.

    Also, the pale rump on B doesn’t seem right for a Vaux’s – it’s too diffuse, without much contrast between the rump and back.

    But I’m with Tristan, my favorite “field mark” is call.

  • Mark Stackhouse

    Yes, A & C seem straightforward as Vaux’s and Chimney, respectively, but B has
    conflicting characters between coloration that says Vaux’s and structure
    that says Chimney. Since I’m a structure-bias kind of a guy, I favor
    calling B a Chimney Swift, even with the caveat that the exact flight
    action can change the apparent wing shape a bit. I’m trying not to cheat
    by using the Pyle character that would be impossible to use in the

    Also, the pale rump on B doesn’t seem right for a Vaux’s – it’s too diffuse, without much contrast between the rump and back.

    But I’m with Tristan, my favorite “field mark” is call.

  • Madeline

    Bird B and C have lighter “eyebrow” just above and forward of the eye, visible in these photos, but surely not visible in the field! But maybe just enough additional information to call Bird B a Chimney not a Vaux’s.

  • Brian E. Small

    How about Bell’s Sparrow and Sagebrush Sparrow 😉

  • Amy K

    The bottom two birds (B & C) seem to have longer wings than the top bird (A), compared to the rest of the bird. My impression is that the bottom two are Chimney, and the top a Vaux’s.
    Very interesting question & quiz.

  • L. Schwitters

    “A” should be a Vaux’s. Based on the bulge of the secondaries “B” and “C” should be chimney. Sibley has a web page where he discusses this in detail.

    Sibley also makes a big deal about changing his mind about Chimney being longer winged. Wing cord data suggests he should change it back.

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