Jose, listen to this:
http://www.xeno-canto.org/80308
http://www.xeno-canto.org/72695
The impression that the frog-like second part of the alam call comes from a=
different direction might simply be caused by its lower frequency (its ave=
rage frequency is only about have of that of the whistle). This frequency d=
ifference alone will cause a different directionality. High-pitched sounds =
are generally emitted more directional than lower ones, depending on the ph=
ysical size of the sound source.
The effect could also be caused by the M/S microphone system itself because=
the polar pattern of any microphone always changes a bit with the signal f=
requency.
Regards,
Raimund
--- In "freitojos" <> wr=
ote:
>
> John,
> I think that it is a bird and a frog, the bird I don't know ( I have pres=
umed luscinia megarhincos but it can be other bird, the frog I think is Hyl=
a meridionalis, but it can also be, hyla arborea or rana perezi. the place =
is well studied by scientists because it is a place that is part of the Uni=
versity of Lisbon,and in the papers there are only these tree frogs and the=
sound seems to me hyla meridionalis.
> Jose
>
>
> --- In "hartogj" <hartogj_1999@> wrote:
> >
> > Hi Jos=E9,
> > I listened to it after balancing the M and S, and I will agree with Dav=
id that it does sound like the calls are coming from two different position=
s. I am not familiar with the specific species, but I could surmise a few p=
ossibilities. It could be a bird and a frog. It could be two birds. It coul=
d be one bird projecting calls in two directions.
> >
> > John Hartog
> > rockscallop.org
> >
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