Emu Emu Society
Journal of BirdLife Australia

Factors affecting formation of flocks of unusual size and composition in Black-necked Storks (Ephippiorhynchus asiaticus) in Australia and India

K. S. Gopi Sundar A , Greg P. Clancy B D and Nita Shah C
+ Author Affiliations
- Author Affiliations

A Indian Cranes and Wetlands Working Group, c/o International Crane Foundation, E-11376, Shady Lane Road, Baraboo, WI, 53913, USA, and Wildlife Protection Society of India, S-25, Panchsheel Park, New Delhi, 110017, India. Email: gopi@savingcranes.org

B Department of Zoology, School of Environmental Sciences and Natural Resources Management, University of New England, National Marine Science Centre, c/o PO Box 63, Coutts Crossing NSW, 2460, Australia.

C Vulture Advocacy Programme, Bombay Natural History Society, A-309, Yamuna Apartments, Alakananda, New Delhi, 110019, India.

D Corresponding author. Email: gclancy@tpg.com.au

Emu 106(3) 253-258 https://doi.org/10.1071/MU05014
Submitted: 21 March 2005  Accepted: 3 May 2006   Published: 18 August 2006


The Black-necked Stork (Ephippiorhynchus asiaticus) usually occurs singly, in pairs or in family groups, and only very rarely in flocks. We describe records of flocks of this species in the Australian and Indian subspecies and discuss the possible reasons for their occurrence. Records of flocks were fewer from India, but flock-sizes were significantly larger. Factors related to flock formation, such as season, habitat quality and water availability, differed between Australia and India. Flocks occurred predominantly in autumn in Australia, whereas there was no relationship between season and flocking in India. Flock-sizes did not differ seasonally for either subspecies or between subspecies. Flocks were composed either of adults only or combinations of young birds and adults. In Australia, occurrence of different types of flocks was not affected by season or habitat. A combination of season and local habitat conditions appear to be affecting formation of flocks in this species.


We gratefully acknowledge the contribution of all the people who shared their unpublished field observations for this paper. K. S. G. Sundar thanks Shashi and M. S. Rana at the Wildlife Institute of India for library assistance, R. Chauhan, Deepu and A. Verma for various help during fieldwork, the International Crane Foundation and the Wildlife Protection Society of India for providing facilities during the writing of this paper, and S. Kittur for various help. G. P. Clancy thanks W. Thompson, R. Jago and V. Clancy for assistance with fieldwork. We thank M. C. Coulter, H. Ford, R. Kingsford, G. Maheshwaran and two anonymous reviewers for providing discussions and critique that improved earlier drafts of the manuscript.


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Appendix 1.  Unusual flocks of Black-necked Storks (Ephippiorhynchus asiaticus) sighted in Australia and India
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