LBBG 13cy M69, Lyondell - Maasvlakte, the Netherlands, 05 April 2003.

An adult bird ringed left white M69, ringed as pullus at the nest, July 06 1991, now in 13cy. These codes were used from the first years the ring project started in 1990 and 1991. There is also a vertical T on the ring. Both green and white rings were used in the early 90's, but green rings haven't been rediscovered for the last two years. They are probably too worn by now and are lost, unlike the white rings. In white rings, no pigmentation is used and therefore these rings last longer.