Bill Evans is an interesting guy. He is currently working with a
grant from the US Gov to determine what changes can be made in the
lights on radio towers so that they do not attract and kill migrating
birds. I have not heard if he made any good headway yet.
On nocturnal calls my design that I believe I posted here called
a "hemi mic" was designed to be an improvement on his "flower pot
mic". It does outperform it as well.
The weakness in his system right now is in screening the false
positives captured within his computer software. Needs a little more
active analysis before saving segments. Editing a nights captures can
be a very large task in some locations.
I think he and everyone playing with this now realizes that a cheap
computer sound card works better than his VCR approach and I suspect
that will be updated on his website sometime.
Cornell also has taken an active role in nocturnal recording of
migrating birds with large arrays. I have not seen it grow to being
an open experiment yet.
Rich
--- In "Martyn Stewart"
<> wrote:
> There is a fascinating site that a guy is dedicated to recording and
> monitoring migratory birds by recording them with a homemade
microphone and
> a VCR recorder. Check this web address out.
> http://www.oldbird.org/
> This is a clip from one of the pages.
>
> The cheapest way to record night flight calls of migrating birds is
with a
> hi-fi video cassette recorder (VCR). These now sell for less than
$75. The
> problem is that VCRs typically do not have microphone inputs. They
have line
> level inputs that are geared for receiving a much stronger signal.
> Therefore, in order to use a VCR to record night flight calls, the
signal
> from the microphone needs to be amplified. The easiest way to do
this is to
> find an audio cassette player that has a microphone level input as
well as a
> line level output. The signal from your microphone goes into the
audio
> cassette player's microphone input and out this machine's line
level output
> into the line level input of the VCR. Typically, in order to do
this, the
> audio cassette player needs to be paused in the record mode so the
signal
> will run through the machine. Inexpensive audio cassette players
that have
> microphone inputs are getting hard to find in stores as they are
being
> rapidly replaced by CD and DVD players which don't have microphone
inputs.
> You might be able to pick up a used or broken cassette deck in a
local
> electronics repair store. The tape drive doesn't need to work. The
deck just
> needs to power up and amplify a signal.
>
> Regards
>
> Martyn :)
>
>
>=20
> Martyn Stewart
> www.Jardiniereco.com
> www.Naturesound.Org
> http://groups.yahoo.com/group/Naturesound/
>=20
> -----Original Message-----
> From: Pieter Wessels
> Sent: Monday, December 08, 2003 8:28 AM
> To:
> Subject: [Nature Recordists] Migrant Birds
>
> Hello,
>
> Does anyone have any information regarding using sound recordings
to
> determine the numbers/species of migrant birds flying overhead
during the
> night - preferably in Britain/UK but references to anything done in
North
> America would be helpful as well.
>
> Thanks
> Pieter Wessels
>
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