Bangladesh (NB), Cambodia (B), China (mainland) (E) (NB), India (B), Laos (B), Myanmar (B), Nepal (B) (NB), Pakistan (B), Sri Lanka (B), Thailand (B), Vietnam (NB).
Vagrant to Malaysia (NB).
India and Sri Lanka to Indochina and southern China.
 
Population
Estimated population is 25,000 (2010) and decreasing.
Status NT
Habitat loss though disturbance, pollution, drainage and hunting of adults and collection of eggs and nestlings from colonies are the main threats.
For more information see BirdLife International Species Factsheet.