Bangladesh, Bhutan, Brunei Darussalam, Cambodia, China (mainland), India, Indonesia, Japan, Laos, Malaysia, Maldives, Myanmar, Nepal, North Korea (B), Pakistan, Philippines, Russia (Asian), Singapore, South Korea, Sri Lanka, Taiwan (China), Thailand, Vietnam.
Indian subcontinent, through Indochina to eastern Cjina, Korean Peninsula, Japan and south through the Philippines and Indonesia. Vagrant to Christmas Island.
Voice
Noisy. A booming, bittern-like, 'kok-kok-kok-kok...', followed by a series of deeper, hollower metallic notes, uttered more rapidly than the first series. Finally a series of clucking notes.
The Field Guide to the Birds of Australia Pizzey, G., and Knight, E., 1997, Angus & Robertson, Sydney ISBN 0 207 19691 5
Field Guide to Australian Birds Morecombe, M., 2000, Steve Parish Publishing Pty Ltd. ISBN 1 876282 10 X
Field Guide to the Birds of Australia Simpson, K., and Day, N., 1999, 6th Edition, Viking ISBN 0 670 87918 5
Reader's Digest Complete Book of Australian Birds 1988, 2nd Edition, Reader's Digest ISBN 0 949819 99 9
What Bird is That? 1984, Revised Edition, Angus & Robertson, Sydney ISBN 0 207 14846 5
Handbook of Australian, New Zealand & Antarctic Birds 1990 - , Oxford University Press, Melbourne ISBN 0 19 553244 9
BirdLife International Species Factsheet