• Natural
  • Yellow: breeding summer visitor
  • Dark green: breeding resident
  • Light blue: passage migrant
  • Dark blue: winter visitor
• Introduced
  • Light green: breeding resident

Data sources:

• Base map: crop from File:A large blank world map with oceans marked in blue.PNG
• del Hoyo et al., eds (1992). Handbook of the Birds of the World 1: 598.
• Madge & Burn (1999). Wildfowl.
• McKinnon & Phillipps (2000). A Field Guide to the Birds of China.
• Balmer et al. (2013). Bird Atlas 2007-11.