Posted by: "Dan Dugan"
> 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.
My own experience is somewhat at odds with this. For many of the species
here traffic starts calling, not inhibits it. A aircraft flying over can
do the same thing. It's actually one of the annoying things for
recording frogs. Call when a car passes, but not in the quiet times in
between.
I've not really seen a lot of avoidance of freeways in the frogs here,
pretty much the same mix calling. It's more dependent on the character
of the wet area involved than the nearby freeway. And water near
freeways is as likely to have a bunch of tadpoles as any other if it's
the sort of water they like. Again, such sites are hard to record.
I agree, the results would be heavily thrown off using small speakers.
It's the low frequency content you need to play.
Walt
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