Hi OBOLers and Tweeters,

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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