At 12:22 pm +0000 23/7/03, wrote:
> Date: Tue, 22 Jul 2003 21:24:32 +0200
> From: Yannick Dauby <>
>Subject: Not likely to be Alytes
>
>hello all !
>
>i just need some frog expert opinions... (hello walt !)
>
>http://kalerne.free.fr/temp/alytes1.mp3
>http://kalerne.free.fr/temp/alytes2.mp3
>
>here are some sounds i recorded by night a few days ago, in the
>south-east part of france, near the mercantour national park (80 km from
>the mediterranean sea). it was just above a village at 1500 meters high,
>around 01AM. i don't know exactly the temperature but i think it was
>around 17-20 degrees celsius (much more friendly than the 36=B0c of today
>in my appartment...).
>i was absolutly unable to locate these animals even if i was sure that
>they were only a few centimeters near (i spent almost 10 minutes,
>looking with my pocket light below the stones around...).
>i have heard several places around this area where these batracians are
>present.
>
>i thought these beautiful singers could be alytes obstetricans, but on
>every nature sounds cd i have, these toads are singing at a much lower
>pitch.
>
>so could anyone identify these songs ?
Nice recordings!
The dominant frequency on your recordings is about 3.4 KHz, and that
is way above the frequencies recorded for continental Alytes (max
about 1300 Hz for A. obstetricans and 1500 Hz for A. cisternasii)
and even higher than the Balearic midwife toad (2.1 KHz). Besides
the frequency spectrum shows a number of emphasized harmonics which
is not the case in midwife toads
the duration of the calls in your recordings is about 44 ms and male
continental midwife toads have calls of 100 ms duration of more (75
ms in male Balearic midwife toads) Females of any species however do
emit calls of 40 ms or even less, but female calls are very soft
(hardly audible).
The envelope of your calls is very similar to that of Alytes though.
If you play your recordings at a 0.35 rate you hear a chorus that
sounds just like Alytes!
>
>if it is the alytes obstetricans, why do they have a so high-pitched
>voice ?
I would be pretty sure that they are not Alytes.
> is it related to atmospheric conditions ?
temperature affects generally the duration of the calls (higher
temperatures-shorter calls) the effects of temperature sometimes are
noticeable on call frequency, but at least with our data for
continental midwife toads in nature, the relationship is not
significant.
>their age ?
size affects negatively call frequency (larger males have lower
frequency calls).
>the
>altitude ?
not really
>the specificity of the region ?
not really, although there is some variation between populations (see
Marquez & Bosch 1995, 1997)
>and do these questions have a sense regarding amphibians in general ?
the general trends (relationship with size, temperature) are quite widespre=
ad
some refs
Bush, S. L. (1997). "Vocal behavior of males and females in the
Majorcan midwife toad." J. Herpetol. 31(2): 251-257.
Crespo, E. G., M. E. Oliveira, et al. (1989). "Mating calls
of the Iberian midwife toads Alytes obstetricans boscai and Alytes
cisternasii." Bioacoustics 2: 1-9.
Heinzmann, U. (1970). "Untersuchungen zur bio-akustik und
=F6kologie der geburtshelferkr=F6te." Oecologia 5: 19-55.
M=E1rquez, R. and J. Bosch (1995). "Advertisement calls of the
midwife toads Alytes (Amphibia, Anura, Discoglossidae) in continental
Spain." Z. zool. Syst. Evolut.-forsch 33: 185-192.
M=E1rquez, R. and J. Bosch (1997). "Male advertisement call and female
preference in sympatric and allopatric midwife toads (Alytes
obstetricans and Alytes cisternasii)." Animal Behaviour 54(6):
1333-1345.
M=E1rquez, R. and P. Verrell (1991). "The courtship and mating
of the Iberian midwife toad, Alytes cisternasii (Amphibia, Anura,
Discoglossidae)." J. Zool. (London) 225: 125-139.
>yannick.
>
>--
>.. yannick -> phonography/improvisation/composition/...
>.. kalerne -> http://www.kalerne.net/
>
--
Dr. Rafael Marquez
Fonoteca Zoologica, Dept. de Biodiversidad y Biologia Evolutiva
Museo Nacional de Ciencias Naturales (CSIC)
Jose Gutierrez Abascal 2
28006 Madrid
Spain
e-mail:
phone +34 91 4111328 ext 1257
fax +34 91 5645078
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