Lesser Black-backed Gull (graellsii & intermedius)
L. f. graellsii N527 August & September 2010, Heemskerk, the Netherlands. Picture Ruud Altenburg.
Ringed adult graellsii "Dutch intergrade". Mantle tone fits local birds, but it may be a migrating bird from a colony further north. Ringed in Spain on a dump in winter.
First image: 02 September 2010.
Below: 04 August 2010.