2 images: adult LBBG BTO G? - 09708, May 03 2004, EMO Maasvlakte, the Netherlands (51.59N,04.02E).
A female with a nest, probably ringed GF 09708. Several foreign ringed adults were discovered in the colonies again in breeding season 2004. First data suggest they involve females mostly. This is in line with other researches (e.g. H. Vercruijsse): males return to the original colonies and are bound to the very near vicinity of their original nest, females may disperse. Since many pairs are formed already on the wintering grounds or at stop-overs during migration, the male guide the females to their colony.
This bird is obvious paler grey than adjacent local Dutch birds (so-called Dutch intergrades). Note the lack of red on the upper mandible.