Sort of sounds interesting. Do others see an unfortunate possible
ambiguity here? In that "frequency" has two meanings of relevance. In
this case by context it appears to mean how often something occurs in
time, not the sound frequency, as in what we hear as pitch. But then
again maybe it is both, in the same way that playing a tape faster
raises the pitch...........
Philip
-----Original Message-----
From:
On Behalf Of Laurie Knight
Sent: Thursday, 6 January 2011 10:25 AM
Cc: Birding Aus
Subject: Urban silvereyes changing their tune
Actually, the article is freely available at
http://rspb.royalsocietypublishing.org/content/early/2011/01/05/rspb.201
0.2296.full
On 06/01/2011, at 9:19 AM, Laurie Knight wrote:
> The abstract for the paper referred to in
>
http://www.theage.com.au/victoria/urban-songbirds-change-their-tune-2011
0105-19g94.html
> is as follows
>
>
>
> Geographically pervasive effects of urban noise on frequency and
> syllable rate of songs and calls in silvereyes (Zosterops lateralis)
>
> Dominique A. Potvin, Kirsten M. Parris and Raoul A. Mulder
>
> Published online before print
>
> Proc. R. Soc. B January 5, 2011, doi:10.1098/rspb.2010.2296
>
>
> Abstract
>
> Recent studies in the Northern Hemisphere have shown that songbirds
> living in noisy urban environments sing at higher frequencies than
> their rural counterparts. However, several aspects of this
> phenomenon remain poorly understood. These include the geographical
> scale over which such patterns occur (most studies have compared
> local populations), and whether they involve phenotypic plasticity
> or microevolutionary change. We conducted a field study of silvereye
> (Zosterops lateralis) vocalizations over more than 1 million km2 of
> urban and rural south-eastern Australia, and compared possible
> effects of urban noise on songs (which are learned) and contact
> calls (which are innate). Across 14 paired urban and rural
> populations, silvereyes consistently sang both songs and contact
> calls at higher frequencies in urban environments. Syllable rate
> (syllables per second) decreased in urban environments, consistent
> with the hypothesis that reflective structures degrade song and
> encourage longer intervals between syllables. This comprehensive
> study is, to our knowledge, the first to demonstrate varied
> adaptations of urban bird vocalizations over a vast geographical
> area, and to provide insight into the mechanism responsible for
> these changes.
> ===============================
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