> That's my problem, too. Spectral display is a good idea, I'll try
> that. I find that it's much easier to collect sounds than it is to
> find time to work on them back home.
Dan,
In those areas in Yosemite, you are likely to record a couple of bat species
that call in the
audible. There are spotted bats with short (5ms) chirp sweeping from 20 KHz to
6-8 KHz
at maybe 125 ms interval. These hunt in less cluttered situations in the
groves. You could
also pickup mastiff bats above the canopy which are very loud and produce ca
20 ms
pulses at longer intervals.
Social calls of many predominantly ultrasonic bats also drop well into the
audible, so it
may not be an aliasing issue, but you can see quickly whether bat calls are
aliased or not
from the way the pattern frequency change in the calls.
If you know what sort of events you are interested in, including even something
as general
as an amplitude excursion exceeding a duration longer than an impact noise, a
fair
number of bioacoustic programs can be configured to search very long files for
events
matching criteria you set and save extracts (of user selected duration) to a
separate
directory. This is a pretty typical task with continuous recordings in wildlife
studies.
Bill Rainey
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