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

[Larry Mcqueen]

There could be another factor here, which favors song purity in the east.
Wherever Willows and Alders overlap, the distinctive characteristics of
their songs are well developed, and this has segregating relevance.   In
other parts of the country where breeding Willows never meet Alder
populations, the type of segregating forces that shaped the two distinctive
songs may be absent in Willow populations, and the more primitive song
variants persist, and some sound much like Alder songs.  There is no need,
in the absence of breeding Alder Flycatchers, for the purity of song type in
the western populations of Willows.

 

Just a thought,

Larry McQueen

 


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

 

   

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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