Pacific tree frogs are about the size of the tip of your little
finger. Yet, tiny as they are, their voices have been measured at
85dBA from 4.5m (15 ft.). Dominant individuals find resonant places to
project their voices far and loudly.
This spring, there are two around our small lap pool. The dominant
frog =96 as it has for the past several years =96 sets up shop in a 1 inch =
outlet pipe at one end of the pool that it uses as a resonator. Its
competition has nothing but an open grass-like area about 3m (10 ft
away) from the main dude in which to vocalize. The open space
disperses its voice and it appears to be much lower in level. Rather
than chorusing and frequency niches, these two compete for temporal
niches; first one will vocalize (usually the dominant one with the
higher-pitched and more urgent-sounding voice), followed by a weaker
and lower frequency sounding second individual.
What was not recognized before, is that they also mimic each other.
When the dominant voice changes, the sub-dominant individual follows.
Here=92s the link to a short clip made about 10 days ago showing both
the temporal niche exchange and mimickry. We=92ll be doing a paper on
this observation but wanted to share it with the group, first.
Bernie Krause
http://soundcloud.com/wildsanctuary/pactreefrogs0411/s-T8vci
Recorder: H4n (internal mics), 44.1/24
Date/Time: 27 Apr 2011, 2023 Hrs
Weather: clear, calm, 50% humidity, 68F/20C
Location: Glen Ellen, CA, approx. 122.5W/38.4N
Wild Sanctuary
POB 536
Glen Ellen, CA 95442
707-996-6677
http://www.wildsanctuary.com
Google Earth zooms: http://earth.wildsanctuary.com
SKYPE: biophony
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