China (mainland) (B), Hong Kong (China) (NB), Japan (NB), Macao (China) (NB), North Korea (NB), Russia (Asian), South Korea (B), Taiwan (China) (NB), Vietnam (NB).
Coastal eastern China from Liaoning through Hebei and Shandong to Jiangsu. Winters from South Korea and southern Japan south to northern Vietnam.
 
Population
Estimated population is 7,100 - 9,600 (2010) and decreasing.
Saunders's Gull (Chroicocephalus saundersi) [XC295970]
by Frank Lambert from Dalian, China, China (call)
Saunders's Gull (Chroicocephalus saundersi) [XC454868]
by Antero Lindholm from Yatsushiro Estuary, Kumamoto Prefecture, Japan (flight call)
Subspecies
Quite similar to Brown-hooded Gull (Larus maculipennis). Sometimes placed in monotypic subgenus Saundersia, based on its compressed bill, its long, slender tarsi, and its incised webs between the long toes.
No subspecies.
Similar Species
Black-headed Gull (Larus ridibundus) is larger, less compact with longer bill and white leading edge to wing.
References
See References.