Wednesday, August 27, 2014

Empid! Oh-No! - 24 Aug 2014

Robin and I were sitting on the back deck this afternoon enjoying the heat and humidity. I looked out toward the Lilac bush next to the house and saw a tiny, non-sparrowy and non-goldfinchy bird with a whitish belly and wing bars.  Flycatcher? The little guy sat for a bit, and bounced off the awning a couple of times while catching insects in flight, then returned to its perch just 10' away. So I ran into the house to grab the camera to see if I could get some photos. It was gone when I got back, so I sat w/ the camera in my lap w/ the hopes that it might return. It did.

I was able to fire off 127 photos while it moved in and out of the bushes, flew off and returned. It never made a sound, and I suspected that I was looking at an Empidonax flycatcher as a first fall bird for the yard. Oh, the cruelty...

Normally, these birds are easy to ID if you can hear them sing: Least Flycatcher (Che-bek!), Acadian Flycatcher (Pit-sEE!), Alder Flycatcher (Vre-bee!), Willow Flycatcher (Fitz-bew!), and Yellow-bellied Flycatcher (j'-biit!). Its a different story, however, when they are silent. But I was determined that I would ID the bird from the photos. So off to hit the books.

Normally, I'd hit the Pyle Guides first, but its more useful if the bird is in hand. So I reached for Kenn Kaufman's Field Guide to Advanced Birding, hoping that he had a chapter on the Empidonax flycatchers. He does!  I'll say it right here, put all of the 'field' guides away, this is the one book to have on your shelf. What a great read.

The first thing I noticed about my bird was the wing bars, so that eliminates Eastern Phoebe, which are normally more sooty-looking this time of year w/ darker cap and white throat transitioning to pale yellow belly (and no wing bars).  But the lack of a distinct eye-ring is suggestive of Eastern Wood-Pewee, yes?

The thing to look for, in this case, is wing projection. On a pewee, the wing projection is long; sufficiently long enough to extend down past the rump and onto the tail. The head is more square, and the bird tends to have a longer, more attenuated appearance.  On this bird the the primary wing projection is distinctively short, barely reaching the rump, so it appears to be an Empidonax. Now to figure which one...

We can probably eliminate ALL of the western flycatchers: Cordilleran, Gray, Buff-breasted, Pacific-slope, Dusky, and Hammond's based on geography. Of the eastern flycatchers I'll also eliminate Yellow-bellied (based on the overall 'pale-gray' appearance), and Acadian (partly geography, but they tend to be greenish and show longer wing projection and thicker, stouter bill) flycatchers.  That leaves the big three for this area: Least, Willow and Alder Flycatchers (the latter two formerly lumped as Traill's Flycatchers).

I eliminated Willow Flycatcher based on head shape (normally more 'peaked' versus round in this bird) and lower mandible color. On the Traill's flycatchers the lower mandibles are normally solid yellow. This bird is showing some evidence of a dusky tip. Though not always the case, the bills on these birds tend to look prominently 'wide' and are uniform yellow in color. Alder Flycatcher tends to be yellower-green in color, as well, so that leaves me with Least Flycatcher.

According to Kaufman, Least Flycatcher is the most numerous Empid seen during migration. The bird tends to look more short-billed, along with short wing projection. The lower mandible tends to show more evidence of a dusky tip, and head is normally smooth and rounded. All of these traits seem to support my Wyandotte bird, so with 95.854% certainty I'm calling this bird a Least Flycatcher.

The eye-ring is less distinctive than I expect, however, but I've seen many photos of Least Flycatchers lacking a distinct eye-ring, so I'm hoping that this bird is not too out of the norm.

As always, I'd love some feedback, and would gratefully accept another lesson in bird ID. I'm pitiful...


I've gotten a number of responses from folks who've read this blog and, although some have agreed with my conclusions,  the consensus is that the bird is most possibly a Traill's Flycatcher, and that I should leave it at that...


Cathy Carroll said...

Hi Jerry,

I'm waiting to take my cat to the vet this morning and so have some unexpected leisure time. I read your post and saw your photos. I agree that Least FC is most statistically likely but, for some reason, I didn't get a Least FC vibe from your bird. The eye ring does indeed have something to do with this. You write about seeing other photos of Least w/o distinctive eye ring and I am not as acquainted with other photos of Least FC as you would be. It just seemed more Willowy or Aldery to me. I do wonder if this is a bird that would need to be "in hand" to make an ID more confidently (and even then, might be difficult). As you know, I am by no means an empid expert, but I love these birds and, in spring, they are amongst my favorites. In fall ... oh gosh. Will look forward to comments from others. Thanks for posting and good yard bird.

Brendan Leddy said...

Eastern Wood Peewee possibly due to the two distinct white wing bars, the forked tail and the white eye ring.

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