Dear colleagues,
The following article is to appear in the new issue of Ornis Fennica:
Bao-Sen Shieh & Shih-Hsiung Liang 2007. Geographic variations and
temporal changes in songs of the Rufous-capped Babbler (Stachyris
ruficeps praecognita). Ornis Fennica 84: 163-172.
Link to download PDF: http://www.birdlife.fi/julkaisut/of/of-english.shtml
Abstract. Song has been an important subject in studying geographic
variation and cultural evolution
across bird populations, but the quantitative analysis of song has been
problematic.
The aim of this study is to investigate the temporal changes and
geographic variations in
songs of Rufous-capped Babblers (Stachyris ruficeps praecognita) using
both spectrographic
cross-correlation (SPCC) analysis and multivariate analysis on
spectrographic
measures.We recorded songs at Shoushan Nature Park of southern Taiwan
from 2001 to
2004 and five other sites including Fushan in northern Taiwan, SunMoon
Lake in central
Taiwan, and Gauchon, Sanpin, Nazenshan in southern Taiwan. The results
showed that
the cross-correlation coefficients of songs between bird samples were
relatively smaller
than those within samples. Using SPCC analysis on first notes instead of
whole songs,
songs of northern Taiwan could be differentiated from those of central
or southern Taiwan.
Results of multivariate analysis on spectrographic measures showed that
mean frequency,
minimum frequency and maximum frequency of the first note were the primary
acoustic parameters responsible for this differentiation. However, there
were no obvious
patterns of temporal changes of songs in the habitat island population
of ShoushanNature
Park, which could have resulted from higher variations among individuals
within the
same year in this high density population.We conclude that the SPCC
analysisworks as a
starting point to examine the geographic variations in songs with simple
structures and a
followingmutivariate analysis is effective in identifying the acoustic
parameters resulting
in those geographic variations.
All the best,
Tomasz Osiejuk
www.behaecol.amu.edu.pl
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