Lesser Black-backed Gull graellsii EU73 6cy, April 22 2002, Missouriweg - ECT, Maasvlakte, the Netherlands (51.59N,04.02E). 

An adult ringed, left orange EU73. Note the dark patch on the lower mandible near the gonydeal angle. This bird was ringed at the nest, July 2 1997 and now in 6cy.