With 3 Heuglin's Gulls (Larus fuscus heuglini) on the left.
Mongolian Gull (Larus mongolicus) is split from Vega Gull (L. vegae) with which it was previously placed. It is morphologically distinct from that species; it differs ecologically, and its vocalizations also appear to be the most distinctive of the species in the "Herring Gull" complex (IOC worldbirdnames.org)