Thanks very much, Paul. I'd had exactly the same thought shortly
after we'd sent out our message. ... So, if you listened for
thrushes last night & this morning, please also report to us a brief
description of ambient noise levels in your area, and how much you
think that may have hindered your ability to detect call notes.

In addition, let us know to what extent vegetation, topography, or
structures surrounding your listening spot may have decreased your
ability to hear sounds from an open sky.

A big THANK YOU from Jim and me to all those of you who counted
Swainson's Thrush calls. The reports are streaming in now, and
people so far have heard everything from zero to hundreds of call
notes. Jim and I will post a summary of the results in a few days.

Jay Withgott
Portland, OR
withgott at comcast.net


At 6:29 AM -0700 9/17/09, Paul T. Sullivan wrote:
>OBOL,
>
>I know this is not my party, but may I suggest one more item that observers
>might report to Jim & Jay? (Thank you, guys, for organizing this. Good
>idea!) Let me suggest folks also report
>5. Ambient noise. Traffic, airplanes, power lines. Water, frogs/crickets,
>etc.
>
>'Twas fun. I'll sent my results off-line.
>
>;-)
>
>Paul T, Sullivan
>
>"As dusk begins to settle, ... Quiet "whit" calls begin to resonate from
>the throats of hundreds of thrushes
>still in hiding in the foliage, and as dark begins to descend upon the
>forest, you can hear the calling birds begin to rise into the sky to resume
>their nocturnal journeys. So ... go into the woods ...very late in the
>afternoon and you will get to experience a truly soul-thrilling event ..."
>
> -- Darrel Faxon, Sept 1, 2005
>------------------------------
>Subject: Swainson's Thrush Night Out
>From: Jim Danzenbaker <jdanzenbaker AT gmail.com>
>Date: Wed, 16 Sep 2009 12:08:18 -0700
>
>Hi OBOLers,
>
>You are invited to participate TONIGHT and TOMORROW MORNING in a
>collaborative effort to begin mapping aspects of the nocturnal migration of
>Swainson's Thrushes in Washington and Oregon.
>
>We're hoping that an informal citizen-science effort of minimal time
>investment can help to address some unresolved questions about this species'
>migration in the West, such as how thrush density varies from place to
>place, whether corridors of migration exist, how migration relates to
>topography and weather, and how these patterns vary between spring and fall.
>
>As a start, we propose that any interested birder in Washington or Oregon
>spend 30 minutes TONIGHT and TOMORROW MORNING listening for Swainson's
>Thrush calls as the birds pass overhead in the night sky, and then report
>the data to us for compilation. We apologize for the last-minute
>organization, but we have just returned home from a trip, the idea just came
>to us, and this needs to be done very soon, as the thrush migration is
>already starting to peter out. We will consider this fall's effort to be a
>pilot run for a more organized effort next spring and next fall.
>
>All you need to do to participate is:
>? Listen outside your home (or in any location open to the night sky;
>quieter is better) between 9:30 and 10:00 pm tonight (Wed. 16th) and again
>from 5:30 to 6:00 tomorrow morning (Thu. 17th).
>? Write down the number of call notes you hear that sound like those of
>Swainson's Thrushes. (Number of calls, not inferred number of birds.)
>? Email your data to the two of us, along with the following:
>1. Brief description of your location (GPS coordinates, Google Map location,
>or nearest cross streets).
>2. Brief description of the topography (flat, along lakeshore, hills 1 mile
>to north, ridgeline 2 miles to east, etc.)
>3. Weather conditions at your site during the listening periods
>(temperature, percent cloud cover, precipitation, wind at ground level, wind
>at cloud level if cloudy)
>4. Any other bird flight calls heard during your listening periods (they
>need not be identified to species)
>
>That's it!
>
>We will compile the data and report back to OBOL and Tweeters.
>
>No need to let us know of your participation in advance; just send us your
>data before the weekend.
>
>For those not familiar with Swainson's Thrush nocturnal flight calls, a
>recording of a large number of them in an exceedingly thick flight together
>may be heard online at:
>http://www.pbs.org/wgbh/nova/kalahari/migrating.html.
>Note that generally only one call note at a time is heard, and rates on most
>nights are less than one per minute.
>Thanks so much. We'll hope for a good flight, and we look forward to
>hearing what you hear.
>
>Jim Danzenbaker and Jay Withgott
>Battle Ground, WA, and Portland, OR
>jdanzenbaker AT gmail.com and withgott AT comcast.net
> Thanks!
>
>Jim
>--
>Jim Danzenbaker
>Battle Ground, WA
>360-723-0345
>jdanzenbaker AT gmail.com
>
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