Cambodia, China (mainland) (B), Guam (NB), Hong Kong (China), India, Indonesia, Japan (B), Laos, Malaysia, Micronesia [Federated States of] (NB), Myanmar, North Korea (B), Northern Mariana Islands (NB), Palau (NB), Papua New Guinea (B), Philippines, Russia (Asian) (B), Singapore, South Korea (B), Taiwan (China), Thailand, Timor-Leste (NB) (P), Vietnam (B).
Vagrant to Brunei Darussalam.
Southern Ussuriland and Korea; central and eastern China and Taiwan. Winters from extreme south-eastern China and Hainan, south through Indochina, Philippines and Indonesia to western New Guinea and occasionally western Micronesia.
 
Population
Estimated population is 10,000 - 100,000 (2010).