Bangladesh, Bhutan, Brunei Darussalam, Cambodia, China (mainland), India, Indonesia, Japan, Laos, Malaysia, Myanmar, North Korea (B), Philippines, Russia (Asian), Singapore, South Korea, Taiwan (China), Thailand, Vietnam.
Vagrant to Guam, Mongolia.
Unknown to Northern Mariana Islands.
Breeds from Manchuria and eastern China west to Assam, northern Burma and Andaman Is, and recently also Japan; winters in Malay Peninsula, Indochina, Borneo and Sumatra, and recently in Ryukyu Is.
 
Population
Estimated population is 25,000 - 1,000,000 (2010).
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