Black-headed Gull U.U L. ridibundus adult, July 11 2003, Tampere, Finland (50.42N,1.34E). 

This bird was ringed in Holland, but probably a breeder in Finland. It shows the common appearance of adult ridibundus in summer, with a dark brown head.

From June into October the complete moult in Black-headed Gulls start with the inner primaries. The inner primaries are dark from below with small greyish tips. From P3 outwards (sometimes from P5 outwards) the primaries show much white, except on the outer-web of P10. The bill and legs turn dark red.

Next moult starts in December and goes on into April. It’s a partial moult including the body and head: the head becomes typically brown with obvious eye-crescents. Some birds develop a pinkish wash on the breast, a phenomenon maybe related to diet. When this moult is completed, birds show the "adult summer" plumage.

This bird was ringed by Frank Majoor, on December 10 2002 at Lorentzweg, Hilversum, the Netherlands. The bird returned to the place next year.