Relative status of two species of migrant sparrowhawks on Java and Bali, Indonesia
Vincent Nijman A D , Francesco Germi B and S. (Bas) van Balen CA Institute for Biodiversity and Ecosystem Dynamics and Zoological Museum, University of Amsterdam, PO Box 94766, 1090 GT Amsterdam, The Netherlands.
B 46 (2F2) Elm Row, Edinburgh EH7 4AH, Scotland, UK.
C Department of Animal and Plant Sciences, Sheffield University, Alfred Denny Building, Western Bank, Sheffield, England, UK.
D Corresponding author: nijman@science.uva.nl
Emu 106(2) 157-162 https://doi.org/10.1071/MU05016
Submitted: 4 April 2005 Accepted: 27 February 2006 Published: 19 May 2006
Abstract
Every autumn thousands of sparrowhawks, mainly the Chinese Sparrowhawk (Accipiter soloensis) and the Japanese Sparrowhawk (A. gularis), migrate from East Asia to western Indonesia. However, the relative abundance of these two species in Indonesia differs between studies, with some reporting Japanese Sparrowhawk being up to ten times more common than Chinese Sparrowhawk, while other studies report the reverse. We assessed the status of these two migrant sparrowhawks on the islands of Java and Bali by comparing four datasets: data from four watch-sites (1992–2004, 108 days, 7698 birds), general surveys (1980–2004, 354 days, 578 birds), museum collections (< 1820–1957, eight collections, 274 birds), and the literature (1902–2004). In the first three datasets, Chinese Sparrowhawk was 2–10 times more numerous than Japanese Sparrowhawk, and data from the literature tended to support this. There were small but significant differences between the two islands, with Japanese Sparrowhawk being slightly more common on Bali than on Java. Systematic study of all available data on the relative abundance of the two species shows there is no evidence that changes in species composition have occurred.
Acknowledgments
We thank the Indonesian Institute for Sciences (LIPI) and the Directorate General of Forest Protection and Nature Conservation (PHKA) for granting permission to conduct research in Indonesia. Thanks go to M. Adams (Natural History Museum, London), T.G. Prins and C.S. Roselaar (Zoological Museum Amsterdam), R.W.R.J. Dekker and H. van Grouw (Naturalis, Leiden), C.M Yang (Raffles Museum of Biodiversity Research, Singapore), Darjono (Museum Zoologicum Bogoriense), J. Dean (Smithsonian Institute, Washington), P. Capainolo (American Museum of Natural History, New York) for access to or data on specimens under their care. C.S. Roselaar is thanked for data on the sparrowhawks in the collection of the Hombult Universität, Berlin. We thank M. Argeloo, D. Augustina, J.H. Becking, N. Blackbeard, R.F. Grimmet, P. Jepson, K. Koyama, F. Lambert, A. Long, S.C.F. Luisterburg, P. Lupianingdyah, V. Mason, F.A. Narata, S. Nuriaeni, Rudiyanto, R. Saryanthi, Sugihartono, and U. Suparman for sharing our observations and data. Financial support was provided by the P.A. Hens Memorial Fund, Martina de Beukelaar Foundation, J.C. van der Hucht Fund, Netherlands Commission for International Nature Protection and Society for the Advancement of Research in the Tropics. J.S. Ash, G. Carpaneto, C.S. Roselaar, J. Wattel, and two reviewers commented on the manuscript for which we express our thanks.
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