David,
Thank you, now I know they are in syntony not only in time but also in freq=
uency!
Here is a geotag to the place:
http://www.freesound.org/people/FREITOJOS/sounds/159548/
Jos=E9
--- In "Avocet" <> wrote:
>
> > As promised in a my previous mail, I uploaded a file on Soundcloud
> http://soundcloud.com/marco-pesente/frog-and-blackbird-duet
> > a true song duet between a Blackbird, Turdus merula, and a Green
> > frog, Rana esculenta.
> > ...
> > I suspect that the frog reacts to the song of the blackbird how it
> > would reacts to any sound of loud intensity, because it happened to
> > me to hear frogs singing as soon as it happens a loud noise such as
> > a passing train or a plane not far.
>
> Marco,
>
> I suspected that my theory that the bird song and frog frequencies
> were matching hadn't worked until I took power spectrums from the
> starts of each call.
>
> The frog has a clear peak at 2150 Hz, below most of the blackbird
> song, but almost exactly 200 ms before each frog croak, the blackbird
> peaked at that frequency. The frog only missed one call but was
> perhaps still listening out when the blackbird sang early. Listen to
> the rercording at 1/5th speed and you can hear this at around 430Hz.
>
> I think we can say that the frog is responding to the main frequency
> in its croak, wherever it comes from.
>
> A frog does not have vocal chords, so it can only make a frequency
> dependant sound with a resonant cavity. Our ears cannot distinguish
> this frequency and only hear a croak, but the frog seems to be
> responding to its own resonant cavity frequency. Presumable this keeps
> different species apart.
>
> We learn all sorts of stuff on this list, like the word "sintony". :-)
> In this case it actually means "same frequency".
>
> David
>
> David Brinicombe
> North Devon, UK
> Cogito cogito ergo cogito sum - Ambrose Bierce
>
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