Sharon Perry and I attended the Bay Area Amphibian and Reptile
Society's meeting in Palo Alto last night to hear "The Effect of
Traffic Noise on Tree Frogs: Do Frogs Like Rock 'n Roll?" by Beth
Dawson. Dawson is doing graduate research at the University of Texas
at Austin.
Three or four people had brought snakes and were carrying them
around. At the beginning of the meeting, which started very late, we
introduced ourselves. A woman named Debbie said she was a member of
the Nature Sounds Society also, and that it was she who had put the
announcement on our announce list. (Debbie, are you here? Thanks!) I
told the group about the Nature Sounds Society's diverse
constituency, and, since they were into show-and-tell, demonstrated
my recording vest.
Dawson's PowerPoint talk, including recordings, was great. She's an
engaging speaker. She described how the calling behavior of Texas
cricket frogs was influenced by proximity to an interstate freeway.
Other species avoid the freeway area entirely, but that species is
found in the same numbers under the freeway.
Dawson found that the noise appears to mask the calls of neighboring
frogs, and the lack of stimulation inhibits calling. The male frogs
would ratchet their calling up to the normal level when she played
back calls near them. The effect of this on breeding is unknown. The
inverse experiment, playback of traffic noise to frogs in quiet
areas, had no significant effect, probably because she was using a
tiny speaker.
-Dan Dugan
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