Gulls
Light-green ring with a 2 alpha-numeric code code
note 1 : rings are placed above the knee (on the tibia) for better observation results in the colony (high vegetation) and on rubbish-dumps. All other colours (with vertical placed codes) above the knee are also part of this project.
note 2 : Same codes can be used by other large gull species. If you have doubts about the species and/or code, please note the age and position of all the rings, including the metal ring.
note 3 : used letters/numers are : A, B, C, D, E, F, G, H, J, K, L, M, N, P, R, S, T, U, V, W, X, Y, Z, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, + and =. Only the letters I, O and Q are never used
note 4 : In this project are also used a combination of two coloured rings with both one letter or number at each tibia.