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THE WILSON JOURNAL OF ORNITHOLOGY • Vo/. 124. No. 3. September 2012 
Pacific, the verbal descriptions of songs in 
literature are suggestive that Z. I. gouldi of the 
present study may be atypical. Tape recordings 
and spectral analyses of island songs elsewhere 
are needed. Spectrographic analyses followed 
with playback testing on several islands would 
help clarify the potential of behavioral isolation as 
an explanation of the ‘great speciator paradox. 
An alternative explanation for the ‘great 
speciator' paradox is that of ‘behavioral flight- 
lessness' (Moyle et al. 2009), in which the 
population, once established post-eoloni/ation, 
evolves extremely sedentary behavior but no 
actual loss of morphological adaptations for flight. 
My hypothesis, in keeping with the concept of 
social selection built around discrimination of 
learned vocal communication signals, is that there 
are colonization attempts between island popula¬ 
tions (or mainland-island), but immigrants are not 
successful in entering the breeding population 
because of behavioral discrimination via male 
territoriality and/or female mate preference based 
upon norms of local population vocal signals 
(Baker ct al. 1981, Boyd and Rieherson 1985, 
Baker 1994. Ellers and Slabbekoorn 2003, Fatten 
et al. 2004. Uy et al. 2009). Unfortunately, few 
studies have been done on vocal communication 
signals in Zosterops , especially in relation to 
island endemism and population diversification 
(e.g.. Slater 1991, 1993; Diamond 1998). Thus, 
explanatory hypotheses of the ‘great speciator’ 
phenomenon remain untested. 
ACKNOWLEDGMENTS 
Thanks to Merrill Baker lor help recording in Esperanto, 
and to her and Laura Tilghmau for helping with camp 
chores and other logistical matters. I also appreciated 
gaining local knowledge of wildlife from the helpful staff of 
the Woody Island facility. Beth and Scott MacDougall- 
Shackleton shared their ideas on approaches to data analysis 
tor this study. Dave Gammon and two anonymous 
reviewers raised many questions and offered insightful 
suggestions. I doubt t was able lo address them all to their 
satisfaction. 
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