Cambodia (E) (NB), China (mainland) (B) (NB), Hong Kong (China) (NB), Japan (NB), Macao (China) (NB), North Korea (B), Russia (Asian) (NB), South Korea (B) (NB), Taiwan (China) (NB), Thailand (NB), Vietnam (NB).
Vagrant to Brunei Darussalam, Philippines (NB).
Formerly more widespread in eastern Asia, range now much reduced; breeding only known from northern Korea, though also suspected in north-eastern China. Winters in northern Viet Nam, southern China and Taiwan, occasionally in Japan.
 
Rarity Status
Currently this species is not classified as a rarity in this country OR information has not been updated.
Population
Estimated population is 1,700 (2010) and decreasing.
Status EN
Habitat destruction through convertion of many coastal wetlands into aquaculture ponds and industrial estates is the main threat.
For more information see BirdLife International Species Factsheet.
Voice
Generally silent. A guttural 'ubuu ubuu' in the breeding season.