LBBG  E914 7cy, May 12 2001, Missouriweg Maasvlakte, the Netherlands. 

Ringed E914 left orange, probably a female. 
Ringed at the nest at Maasvlakte July 10 1995, now in it's 6^th summer. 
Note the brown hue on many of the upper-part feathers and coverts.

Also note the rather slender bill, lacking the clear gonydeal angle, almost Common Gull-like in appearance. This strongly points to a female.

LBBG adultE914, August 18 2001, Missouriweg Maasvlakte, the Netherlands. 

P6 shed, p7-p10 are still old.