Intriguing Empid, Rocky Mountain National Park, Larimer County

[Ted Floyd]

Hello, Birders.

The long and the short of it: There's an intriguing Empidonax flycatcher just beyond campsite #13, Loop B, in the Aspenglen campground, Rocky Mountain National Park. Perhaps the 7/22 DFO field trip can try for the bird?

The rest of the story:

Saturday morning, June 7, I digibinned and audio-recorded an Empidonax flycatcher whose ID has eluded me. I tried putting the bird in various boxes. Then I emailed the evidence to various experts, and I got an amazing diversity of responses:

* Willow

* most likely Alder

* Acadian

* Acadian or Alder

* Hammond's

* Dusky

* Dusky or Gray

* some hybrid

* a hybrid, but not Hammond's x Dusky; Dusky probably involved, maybe Dusky x Gray

* let's not rule out Pine Flycatcher as a parent

Whatever this bird is, it's not typical.

Photo-documenting empids with binoculars and and iPhone, I have found, is hard. So the digibinned photos are poor. Here they are, for what it's worth:

http://tinyurl.com/RMNP-Empid-01

http://tinyurl.com/RMNP-Empid-02

The audio is better:

http://www.xeno-canto.org/181520

Arch McCallum, one of the experts who've reviewed the evidence, offers some sage advice: Don't try to put this bird in a box.

What do you think it is?

Ted Floyd

Lafayette, Boulder County, Colorado

[Paul Hurtado]

I'd love to dig deeper and do a proper analysis of the recording, but a quick glance at the photos and some browsing of Empidonax sp. call notes on xeno-canto.org has me leaning heavily towards Dusky. 

1. The tail shape and dark tip on the underside of the mandible visible in this composite (and enlarged) photo of Ted's two photos seems to rule out "Traill's", Acadian, etc. All those broad-tailed species with an unmarked underside to their mandible.

http://www.facebook.com/photo.php?fbid=10203697297931524&set=p.10203697297931524&type=1&theater

2. Browsing call notes on xeno-canto, it seems like Dusky is a really good fit for both the pitch and inflection.  I can't find similar call notes from Hammond's or other species, however I didn't do an exhaustive search, nor did I read up on described call notes from Dusky or these other species.  

I've opened up a discussion on xeno-canto.org regarding the ID of the bird in the recording, so hopefully some additional Empidophyles chime in on the ID.  That discussion is at http://www.xeno-canto.org/forum/topic/9362

Lasly, if you've read down this far, and all this nit-picking over audio details is both new and fascinating to you, I would encourage you to head over to EarBirding.com -- an excellent resource with information about birding by ear and studying sounds in a bit more detail than the pneumonics we're used to seeing in field guides.  Plus, that website is run by Colorado's very own Nathan Pieplow and Andrew Spencer and is full of content related to identifying Colorado birds by their vocalizations.

Good birding,

-Paul Hurtado

--
You received this message because you are subscribed to the Google Groups "Colorado Birds" group.
To unsubscribe from this group and stop receiving emails from it, send an email to cobirds+u...@googlegroups.com.
To post to this group, send email to cob...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/cobirds/BAY177-W193774893318CCF6EA3A3BC0110%40phx.gbl.
For more options, visit https://groups.google.com/d/optout.

--
Paul J. Hurtado
Postdoctoral Fellow, The Ohio State University
Mathematical Biosciences Institute, http://mbi.osu.edu/
Aquatic Ecology Laboratory, http://ael.osu.edu/

E-mail: hurta...@mbi.osu.edu
Webpage: http://people.mbi.ohio-state.edu/hurtado.10

[Nathan Pieplow]

As Paul deduced, Ted's intriguing Empid is a Dusky Flycatcher -- one that's quite upset.  Reasons why it's a Dusky at http://www.xeno-canto.org/forum/topic/9362.

Thanks to Ted for a great recording, and to Paul for a good analysis.

Nathan Pieplow
Boulder

To view this discussion on the web visit https://groups.google.com/d/msgid/cobirds/CABpQ-FU%2BrfYAJO-7ymsRd9KwFadCZzkJHzBF--TrwDCKrQq4bA%40mail.gmail.com.

[Ted Floyd]

Thanks to Paul Hurtado and to Nathan Pieplow for their contributions. Not sure I agree that this bird's vocalizations are "typical" (per discussion at Xeno-Canto) for Dusky Flycatcher. I randomly grabbed this Chaffee County Dusky Flycatcher recording from Xeno-Canto:

http://www.xeno-canto.org/110022

That bird's "wit" call rises from 2.5 kHz to 5.5 kHz, and it sounds about "right" (more on that below) to my ears for Dusky Flycatcher. The "wit" call of the bird in Rocky Mountain National Park rises from 3 kHz to 6 kHz. In human musical terms, that's comparable to going from a middle C to the E above middle C; or, if you want a direct comparison, it takes you from E'''' to G''''.

In the following recording, the first six notes are of the "wit" call of the bird from Rocky Mountain National Park:

http://www.xeno-canto.org/181520

I'm not saying that the bird in Rocky Mountain National Park isn't a Dusky Flycatcher (and as Nathan says, the bird seems upset, which might well affect the bird's "wit" note). But I'm interested in how different it sounds, to my ears, from the Chaffee County bird. Perception of pitch varies greatly from human to human, from culture to culture, and from musical tradition to musical tradition. To some humans, there's a big difference between C and C-sharp, let alone between C and E. To other humans, such qualities as timbre and intonation are more distinctive.

All of which goes to show: Birders' fallible ears and suggestible brains are no substitute for a sound spectrogram!

I'm curious: Do y'all hear differences between the "wit" calls of the Chaffee County and Rocky Mountain National Park birds?

For sure, this has all been an interesting learning experience for me.

Ted Floyd

Lafayette, Boulder County, Colorado

[Ted Floyd]

P.s. Here are links to recordings of some inarguably "normal" songs from that same Saturday, June 7, in Rocky Mountain National Park:

Green-tailed Towhee, http://www.xeno-canto.org/181523

MacGillivray's Warbler, http://www.xeno-canto.org/181522

Wilson's Warbler, http://www.xeno-canto.org/181521