Hi Tweeters,

For any night flight enthusiasts out there, I posted this to OBOL tonight in
response to questions concerning night flights.

Jim
--
Jim Danzenbaker
Battle Ground, WA
360-723-0345
jdanzenbaker at gmail.com


---------- Forwarded message ----------
From: Jim Danzenbaker <jdanzenbaker at gmail.com>
Date: Thu, Sep 10, 2009 at 9:12 PM
Subject: Re: Night Flight
To: Douglas Kirkpatrick <kirkpat at charter.net>
Cc: obol <obol at oregonbirdwatch.org>


Doug,

As Mike Patterson stated, the spectacle of Swainson's Thrush migration seems
to be patchy. It doesn't seem to be a broad swath of birds that is evenly
dispersed across the night sky. Last Friday morning, I left the house at
3am and had loads of calling thrushes flying over the house. I drove about
five miles west, got out and listened and heard nothing. I think it would
interesting to note where people are located who hear all these thrushes
overhead and plot them on a map then connect the dots to see if these
streams of birds are following certain topographical features. (Should we
have an official "Night Flight" night where everybody goes out at a certain
time and listens and reports? - late evening and early morning if the stream
fluctuates?) Yes, in this case, information on where they are *not* heard
is just as important as where they *are* heard. I attempted to do this
several years ago and collected data from great OBOL and Tweeters volunteers
but, unfortunately, had very little time to critically analyze the data and
report back to them. I hope to do something with this information in the
future and volunteer names will be mentioned. Interestingly, I only hear
Swainson's Thrushes in the Fall. I have never heard a night flight over my
house in Battle Ground in Spring like folks in the Eugene area do.
Therefore, I can only assume that the streams of Spring migrants are in
different places than in the Fall.

Regarding listening to them and separating them from other calls, that is
difficult. I have found that the best time to hear the peak number flying
over is about a half hour before sunrise. This is presumably when birds are
ending their night flight and descending. Therefore, more birds are heard.
A recent post on another listserve surmized that an *average* nocturnal
migrant flies at *about* 5000 feet. Can you hear a calling Swainson's
Thrush at 5000 feet? Who knows - probably not since that's almost a mile.
Are the ones that we hear during the night (before descending flight in the
morning) flying at less than 5000 feet and then that number is augmented in
the early morning by birds descending from 5000 feet? Who knows. I do
strongly feel that if you are in an area with not many other night sounds
and you happen to be under one of the "streams" of migrants, you will hear
them (assuming that you can hear thrushes, warblers, etc during the day).
As far as separating the Swainson's Thrush calls from, say, tanagers and
grosbeaks or something else like that, I can't comment because I'm not
familiar with the night flight calls of those other species. However,
thrush calls are a night and day difference compared to migrant warbler and
sparrow chips. I am currently at the Western Field Ornithologist meeting in
Boise, Idaho and we will do a couple of night flight field trips where we
will hopefully hear something. Ted Floyd who does incredible work with
night flights over Boulder Colorado will be there and hopefully we will hear
other species besides Swainson's Thrushes.

I don't listen from a hot tub, just have a window open and listening from
the luxury (?) of my home.

Keep your ears and eyes skyward!

Jim
--
Jim Danzenbaker
Battle Ground, WA
360-723-0345
jdanzenbaker at gmail.com

On Wed, Sep 9, 2009 at 2:06 PM, Douglas Kirkpatrick
<kirkpat at charter.net>wrote:

> Greetings, All,
>
> OK, so I went out last night and listened very carefully but only heard a
> bazillion crickets and some remote highway traffic.
>
> How exactly does one listen for/identify Swainson thrushes or other birds
> at night? Are you guys using parabolic dishes, sonar receivers, small
> children with perfect hearing or what? Does it have to be 5 am ? I've heard
> Swainson's and other during the day but at night the crickets are
> overwhelming my auditory scanners (aka ears.)
>
> Thanks.
>
> Doug Kirkpatrick
> Medford
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman1.u.washington.edu/pipermail/tweeters/attachments/20090910/d4d55699/attachment.htm