Hi Vicki
Yes the recordings are stereo (a twin omnidirectional mic "Soundmeter"
see http://www.wildlifeacoustics.com/), and so even though we have not
yet done it, phase differences should tell us the direction of the calls
(well down to two possible directions with just two mics I think). The
software by the same manufacturer called "Song Scope" IIRC allows such a
phase difference determination.
The software also allows sonogram "recognisers" to be set up to identify
particular calls. Its main use is scan many hours or days of recordings
for those "recognised" calls and to log them in an excel type database.
Compared with a human ear and brain combination however, it only has
about 80% to 90% success rate. This rate is determine for each recording
by listening to say 15 mins of "typical" sample and running the software
over the same part. From that sample the relative detection success rate
for the software vs human ear can be determined for that recording and
then the software result from scanning the days of recordings is scaled
up by that factor - beats listening to days and days of recordings in
real time and you always have to log to help you to zero in on likely
interesting bits and listen to them anyway.
But for possible mimicked calls it isn't able to distinguish the real
call from the mimicked ones - understandable when we have trouble with
it too. And of course the recordings are not that good either despite
high sampling rates and deep bit depth ... mainly because the mics have
to be omnidirectional to pick up bird cals from any direction. This
means of course that they also pick up sounds from insects (especially
crickets and cicadas !!!), leaves rustling in the wind, rain drops
falling through the leaves (it's a rainforest and so plenty of rain),
overhead aircraft, passing bushwalkers talking, distant motor vehicles,
etc, etc. And so as recordings of bird calls they leave a lot to be
desired. But it's still a really good way to be able to get lots of data
without having to actually stay there for days or weeks and the birds
are undisturbed and call more freely as well.
>
> Stereo recordings could be useful for unmanned surveys of Rufous
> Scrubbirds, i.e. so that you could tell the direction of the calls.
>
>
> Vicki Powys
> NSW
>
>
"While a picture is worth a thousand words, a
sound is worth a thousand pictures." R. Murray Schafer via Bernie Krause.
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