LBBG E558 5cy, May 12 2001, Dintelhaven Maasvlakte, the Netherlands. 

Ringed E558 left green. Ringed at the nest at Maasvlakte June 15 1997, now in it's 5cy. Note the very small tips of the primaries, relatively small white mirror on P10, the hint of black on the gonydeal angle and the many brown feathers in the upper parts. All these features are believed to fit immatures better than adults. Nevertheless, this proved to be a very territorial bird and was probably already breeding in the Dintelhaven colony in it's 5cy.