werainey wrote:
> Bernie,
> There's some older commentary on noise from flowing water affecting foraging
> by bats. In
> 1986 Herd reported on noise from fast and slow flowing water (up to 80 kHz),
> noting fast
> flowing water was louder up to about 70 kHz. He discussed two species of
> North American
> Myotis that often hunt near water and pointed out that the species with the
> higher typical
> echolocation frequency (50 kHz) was commonly encountered hunting over fast
> while the
> other (40 kHz) was not. This is not exptl study like the one Gianni
> mentioned, so other
> factors could be involved.
>
>
>
>
For what it's worth, one time I was monitoring for meteors and fireballs
with a handheld McGreevy WR-3 ELF/VLF radio receiver which operates at
between 0.2 - 11 kHz. Whenever I switched on the radio bats would go
into a frenzy and dive right down to the radio. I'm not sure if they
were attracted to the sound or if it was annoying them. After a few
moments of bats diving at my handheld radio I got the message to switch
the radio off.
Thomas Ashcraft
New Mexico
|