[obol] alder flycatchers in Oregon (kinda long, and a little geeky, but no sonograms, I promise)

[Moore, Randy]

Couple of things to do with the recent spate of alder flycatcher sightings and subsequent discussion:
 
I'm fully on board with questioning the vocal ID of this particular complex, especially without recordings in hand (they're coming, I swear).  The two species can make remarkably confusing sounds, but I wouldn't throw the potential baby out with the bathwater just yet, and here's why (slightly geeky stuff alert):  
 
All bird songs exhibit a series of physical characteristics; things like frequency, cadence, note structure and duration, amplitude, etc., that taken together, determine how we experience the sound.  Some of these songs are notoriously difficult to tell apart.  I think it's useful, though, to parse difficult to separate bird sounds into two groups: confusing and overlapping.     

*	
	Confusing sounds are those share some, but not all, physical characteristics.  They are hard to separate because our ears (or more appropriately, our brains), without a lot of listening practice, focus on the physical similarities of the sounds instead of the differences.  Like FITZ bee-you and fee-BEE-oh; the quality (frequency range and modulation) of the sounds is very similar to us, leaving a subtle difference in accentuation and syllabism for separation purposes. 
*	
	Overlapping sounds share so many physical characteristics that they are, in fact, inseparable by our natural equipment.  At least most of our equipment; some people are senstive to differences in physical characteristics of sound that would elude 99.9 % of us.  Chip notes of some closely related warbler species fall into this category.  

So why is this distinction relevant?  To my knowledge, when willow and alder flycatchers are singing their advertising songs, there is no overlap in the accentuation and syllabism I mentioned above.  It's consistently different and if both species bred commonly in Oregon, I'm betting there wouldn't be nearly so much discussion about potentially confusing the songs. 

 Secondly, I'd be astounded if the lack of Oregon records didn't reflect the difficulty of IDing them, rather than an actual lack of occasional occurrence.  Put another way,  I bet they're less rare than we think they are.  Given alders' long-distance migratory nature and Oregon's proximity to BC breeding grounds, it would amaze me if some of those non-vocalizing Traill's flycatchers that show up in spring weren't sneaky alders.  Most of the other species that share a boreal breeding range but migrate (generally) east of the Rockies show up here pretty much annually (I think, but I obviously don't have a great grip on Oregon bird records yet!).  The interesting exception may be gray-cheeked thrush, another skulky bird in a difficult to separate species complex that probably doesn't sing a great deal on migration.

cheers,

randy

corvallis


________________________________

From: Mike Patterson [mailto:celata at pacifier.com]
Sent: Thu 5/31/2007 12:37 PM
To: obol
Subject: Re: [obol] RBA Alder Fly OREGON CITY



The "FITZ-bee-oh" (distinctly 3-parted) and "freeBEER" calls
are not unusual around the P-Ranch and are genrally regarded
as Willow Flycatchers.  I have heard the "freeBEER" call in
clearcuts in the Coast Range as well.  Willow Flycatchers are
known for a far more variable repetoire than Alder Flycatcher.

I recommend that any recordings be sent to one of OBOL's
sonogram masters (I can mke sonograms, but can't analyze them).
I will bet that the recent Alder reports will fall into the
"FITZ-bee-oh" pile rather than the "RAY-bee-oh" pile.

But as always, I'm willing to be convinced otherwise....

Tim Rodenkirk wrote:
>
> While jogging south of Benson Pond along the CPR at
> Malheur this past weekend, I heard a flycatcher doing
> a freeBEER call/song that seems identical to what an
> Alder sounds like.  Not the first time I've heard this
> call in Oregon.  I promptly forgot about it, thinking
> it would be an impossible record to get by OBRC.
> Also, I'm not convinced they can't sound similar- but
> I'm no expert. I heard the bird on 5/24 maybe a tenth
> of a mile or south of Benson Pond on the CPR- maybe
> the bird is still around?  I did not stop to observe
> it, figuring it was just another Trail's Flycatcher.
>
> Tim R
> Coos Bay
> off to Alder Flycatcher country in a few weeks
>

--
Mike Patterson              
Astoria, OR                   
celata at pacifier.com 

Malheur NWR Photo Essay
http://www.surfbirds.com/blogs/mbalame/archives/2007/05/malheur200705.html



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