My hubby has lost his high frequency hearing so we have sent for one of Lang
Elliotts magic boxes. I think it is going to be fun for Jim to pick up the
birds he is missing but I cannot really wait to try it on things like the
small mammals and bats. Jim thinks it is his but I think we are going to be
doing some fignting for it.
Barb Beck
Edmonton
-----Original Message-----
From: Jim Morgan
Sent: August 8, 2004 9:11 PM
To:
Cc: Greg Clark
Subject: [Nature Recordists] Ultrasonic alarm call for Richardson's ground
squirrel
The following message has been posted by Jim Morgan for Greg Clark, a Nature
Recordists member, that is having temporary posting dificulities.
In the 29 July 2004 issue of "Nature" there is an article concerning an
ultrasonic alarm call for Richardson's ground squirrel (Spermophilus
richardsonii) (The authors refer to Canada in the article) . The alarm call
frequency is very narrow, close to 50khz, and short, only 238 ms. The
authors comment "To our knowledge, ultrasonic alarm calls have not
previously been detected in any animal group, despite their twin advantages
of being highly directional and inaudible to key predators." The authors
used playback and a pure tone at the dominant call frequency (along with
other control tones) to investigate the behavior of the squirrels. The pure
tone elicited "vigilant" behavior similar to the native call.
I have two species of ground-dwelling squirrel that live in my backyard in
Arizona and I have a means of down-sampling the high frequencies so that I
can detect them. Perhaps I will hear a short click when the squirrels see
me. Those of us who have the means to detect ultrasonic signals, and are
around squirrels (especially ground squirrels) probably should have a
listen for these frequencies in case they are found in other squirrels.
I don't have a transducer that would transmit ultrasonic tones, but this
might be another way to see if the squirrels take notice. I imagine the
dogs in the neighborhood would be interested.
Greg Clark
[Non-text portions of this message have been removed]
"Microphones are not ears,
Loudspeakers are not birds,
A listening room is not nature."
Klas Strandberg
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