jfjulien2
Date: Tue Jul 10, 2007 4:08 am ((PDT))
Hola,
that's an insect for sure. Bats can emit a rapid succession of
very frequency-modulated sounds (almost vertical on a sonagram) when
capturing (or attempting to) an insect but the pattern is different
and it does not sound the same at ear. It is that bat workers call a
"buzz". Usually the very end of the buzz is emitted at frequencies
lower than the usual echolocation calls of a given species.
However, you can encounter in and around Sevilla a low
frequency (11 to 16 kHz) emitting bat, the Greater Noctula (Nyctalus
lasiopterus), now infamous after the demonstration by a Coto Do=F1ana
based team of its bird-eating habits. Its calls are loud, with a low
repetition rate (0.4s to 0.9s intervals) and it is fairly easy to
record it with plain audio equipment. It roosts in Sevilla and uses
to forage above Do=F1ana.
--- In "dobroide" <> wrote:
>
>
> noticed a series of ultrasonic calls in a recording I did the other day
> at dusk in a scrub/juniper area near Donana, S Spain.
>
> sound sample
> <http://freesound.iua.upf.edu/samplesViewSingle.php?id=3D37231>
>
> spectral view
> <http://farm2.static.flickr.com/1034/761823513_33cf92597c_o.jpg>
>
> 15-21 kHz (and above, obviously), they are strong and show a pattern. At
> first I thought of a bat, but maybe they were done by an insect (?).
> Similar calls appear often during summer so I would appreciate any
> hint. Just curious.
>
> Regards
>
> D.
>
>
>
>
>
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