Divergence in New Holland Honeyeaters Emphasis T

Authors: Steven Myers Geoffrey Brown Sonia Kleindorfer

Publish Date: 2009/10/09

Volume: 151, Issue: 2, Pages: 287-296

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Abstract

Studies of island versus mainland populations have provided insights into processes that shape adaptive divergence eg through selection in allopatric populations as well as patterns of morphological change In this study we compare the morphology and foraging behavior in New Holland Honeyeaters Phylidonyris novaehollandiae between Kangaroo Island and the South Australian mainland We 1 provide descriptive information on morphology traits across populations to test previously described differences 2 test the prediction that island birds will have a wider foraging niche different use of foraging substrate and different foraging techniques and 3 test for evidence of reduced prey diversity on islands as evidenced by longer foraging time The results provide support for the predictions Island birds were larger than the mainland birds in tarsus 25 and bill length 37 had a wider foraging niche mostly due to greater insect consumption and foraged more from the bark and air sallying Consistent with other studies of island biogeography at least one common mainland predator and several bird species are absent from Kangaroo Island which may facilitate niche expansion in the island birds A wider niche could also be favored by lower prey diversity on islands a depauperate community in this study island birds had longer foraging times than mainland birds which may be evidence for lower total prey densityThis study was funded by the Australian Research Council We thank the Department for Environment and Heritage DEH Birds for Biodiversity program and the Conservation Council of South Australia for financial support awarded to SK We extend sincere thanks to Peggy Rismiller and Michael McKelvey at Pelican Lagoon Research Centre for logistical support and for stimulating discussion We also thank Beth Schlotfeldt Margot Oorebeek and Sarah Lambert for field assistance and critical comments on the manuscript All procedures followed the Guidelines for the Use of Animals in Research Flinders University and were approved by the Animal Welfare Committee of Flinders University permit E190 E203

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