Living the Scientific Life (Scientist, Interrupted)

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[Mystery bird] Willow Flycatcher, Empidonax traillii, photographed near Park City, Utah. [I will identify this bird for you in 48 hours]

Image: Terry Sohl, 29 July 2009 [larger view]

Canon 50D, 400 5.6L lens.

Please name at least one field mark that supports your identification.

Review all mystery birds to date.


  1. #1 Elizabeth
    September 28, 2009

    Gray flycatcher. The bird has the shape and beak of a flycatcher. It’s a gray flycatcher because of the light yellow/green breast feathers and subtle eye-ring. The second closest match, the pacific-slope flycatcher, has a brighter eye ring and two very distinct wing bars.

  2. #2 Gina
    September 28, 2009

    Without seeing and/or hearing this bird in the field, in it’s habitat, I’m uncertain – so I’m guessing that this bird may be a Willow flycatcher – note the broad-based bill, orange-yellow underneath (gray flycatcher has a noticeable black tip that extends to the lower mandible). Other field marks I used include the subtle eye-ring, dull wingbars,short primary projection, and the slope of the forehead (“flat-headed” look from the bill up). I can’t see white edges on the tail as would be an identifying field mark for the Gray flycatcher. I give up!

  3. #3 Adrian
    September 28, 2009

    Enough of the Empidonax already. It’s either Willow or Grey, I think. Pacific -slope should show more white behind the eye and have a broken eyering, I think. My Nat Geo guide says that some Grey have an all-orange lower mandible so I can’t eliminate this. Can they be separated by wingbar colour? Have I mis-identified all Empi’s up to now? I don’t know without a soundtrack.Rant over.
    ps excuse the spelling of gray, it’s just us crazy Brits.
    pps Congrats to the photographer, a superb picture.

  4. #4 John Callender
    September 28, 2009

    I cheated and looked in the back of the book for the answer, so I won’t guess. Cool shot of a cool bird, though. 🙂

  5. #5 David
    September 28, 2009

    OK, I am eliminating Pacific-slope (Empidonax difficilis) because the photo is from Utah, but the similar Cordilleran (E. occidentalis) could be found there, and although field marks for both include a distinct pair of wingbars, this could be an immature (wingbars buffy) Cordilleran… my impression of the Willow (E. traillii) is that it should be slighty more olive than as in this photo which means that it could therefore be a Gray (E. wrightii) and seeing as the three best distinguishing characteristics for the genus Empidonax are voice, breeding habitat, and range, I think I’m having better luck with all these African Nectarinia/Cinnyris Sunbirds!

  6. #6 psweet
    September 28, 2009

    I think you can rule out Pacific-slope and Cordilleran because of the pale gray throat. Both the ‘western’ flycatchers have yellow throats (the hard one there would be an out-of-range Yellow-bellied). In late July Pacific-slope should be unlikely in Utah, but they migrate regularly through the lowlands of Arizona, so an August P-s in Utah wouldn’t surprise me. Unfortunately, I don’t think they’re distinguishable on sight alone.
    This bird seems to me to be a bit short-tailed to be a Gray, the wing-coverts seem a bit too pale to be a Least, and the face seems to pale to be a Gray. Which leaves me with ….


    Given the way the pale face fails to contrast with the throat and the wing-coverts blend into the back, I’m going to go with Gray, and chalk up the short-seeming tail to inexperience. Gray Flycatcher.

  7. #7 psweet
    September 28, 2009


    That should read “the face seems to pale to be a WILLOW.”


  8. #8 Michelle Scholz
    September 29, 2009

    I’m going with Willow Flycatcher even though the bird is gray-colored because of the all-orange lower mandible and almost-absent eyering.

  9. #9 David
    September 29, 2009

    OK, time to play my ace- this must be an interspecific cross between a Gray and a Willow, and in the interests of fairplay, all those who identified either get the credit for this new species of flycatcher- Empidonax ginabethadesweetii

  10. #10 "GrrlScientist"
    October 1, 2009

    using my field guides (and yes, i DO have ALL of them!), i also narrowed this empid down to either grey or willow flycatcher, but opted to identify it as a willow flycatcher because i think that species is “cuter” than grey. i’ve studied my field guides and cannot, for the life of me, define “cute” as portrayed in the field guides, but i can sure see it in the image above. looking through all my field guides, i decided that color was not a good clue in this image for two reasons: first, the sun has washed out the bird’s color in the photograph and second, the bird is in well-worn plumage, so color was not a good indicator, leaving color pattern as a reasonable clue. however, i will admit that i think i see a faint yellow edge to the primaries, which might be real or the result of wishful thinking. i also found beak color and length as well the the size of the bird’s head to be helpful clues.

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