The smallest gull in the world, the Little Gull is common across Eurasia.
The underside of wings is blackish. 
During the breeding season, the head is black.
In winter, the head shows a dark spot behind the eyes and on the cap.

First 4 photos: Loosdrecht, The Netherlands, 15 April 2011
Last photo: De Blocq van Kuffeler Marina, Almere, The Netherlands, 11 July 2019