Black ring with a yellow three alpha-numeric code.
note 1 : used letters/numbers are: A, C, F, H, J, L, M, N, P, R, T, U, V, W, X, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0.
note 2 : c-ring on left tarsus means birds ringed in Bohemia (West) and c-ring on right tarsus means birds ringed in Moravia and Slovakia (East).
note 3 : project started in 2017 : codes where letter "A" is at the third position are now used.
note 4 : project starts in 2018 in Slovakia.
used codes are : letter "U" or "W" is at the first position and letter "A" at the third position.