Syd Curtis wrote:
> Would any Naturerecordist care to comment on ventriloquism in birds?
>
> I have encountered occasional references in the literature, but it seems =
to
> me to be a physical impossibility. Am I right?
>
The 'evidence' is that humans find it difficult to locate some birds
from their calls. There are some pitches of sound that are difficult for
us to localize, but they are in very low frequencies that few birds use.
There is also reflection, which is a "real" misdirection but not due to
ventriloquialism, although there is a frog, I believe, that positions
itself to enhance (amplify, alter, reflect) its own calls and no doubt
birds do this too.
But none of this is what you mean, I suspect. So, I think of stereo
systems that can create a sound image wider than the distance between
two speakers by messing about with phase relationships. This is a real
'throwing' of the sounds. Then I remember that a bird has two syrinxes,
allowing it to make two simultaneous sounds, and I would not be
surprised at all to find that birds can introduce similar phase
manipulation in order to throw their voices. All speculation, but it
seems reasonable, and the birds have had, in very round numbers, about
100 million years to work out the details.
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Chuck Bragg, Pacific Palisades, CA
Membership, Newsletter, Web manager
Santa Monica Bay Audubon Society
www.smbas.org
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