Today I visited the seashore at the Platja de Can Camins in El Prat de Llobregat, Barcelona, Spain, and I saw this gull. Maybe Audouin's gull, and as if he/she would have some kind of ring too.
Probably zooming is necessary. I could not took closer photos. The bird flown away after a few minutes.
Bird experts probably can tell what kind of gull is this.
A zoom in.
By the way, on the way to the shore, I also visited the Mirador del Camí de Valéncia. An observation point for plane spotters. I have not even heard about such a thing so far.
Have a nice day and have a nice weekend.
All the best. Greetings and much love from Spain.