(light) Blue ring with white 3 alpha-numeric code : 1 letter (R) and 2 numbers.
note 1 : until 1999 some 145 rings have been placed from which 85 light-blue and 23 green.
note 2 : the light-blue is quick used and turns into 'white', therefore greens rings have been used since 1999. As first letter is used A, C, M, E, H, J and a second letter is used A, C, E, H, J, K, L, M, N, P, R, T, V, W, X, Y. As number is used 1 till 9, but the number 0 is not used.
note 3 : since 1999 in three other places in Germany all together 3 chicks were ringed with green rings.