Common Tern

Yellow flag with a black three alpha code (on left tarsus) and metal ring (on right tarsus).

note 1 : First letter R and flags are coded from  RAA to RZZ using 18-letter alphabet (A, C, F, H, J, K, L, M, N, P, R, S, T, U, V, W, X, Z).

note 2 : birds ringed in Romania starting with 2021.

note 3 :

Red ring with a white 3 alpha-numeric code.

note 1 : all combinations of letter “P” and numbers/letters in various positions of the code are being used. 

note 2 : birds have been ringed as both breeding adults and pulli at the Rockabill and Dublin Port Tern colonies

note 3 : used numbers are : 1, 2, 3, 4, 5, 6, 7, 8, 9, 0. 

note 4 :

White ring with a black 3 alpha-numeric code.

note 1 : most birds are ringed as pulli and have the c-ring on their left tarsus and a metal ring on the right.

note 2 : used combinations are : letter "P"/ number/ number OR number/ letter "P"/ number OR number/ number/ letter "P".

note 3 : used numbers are : 1, 2, 3, 4, 5, 6, 7, 8, 9, 0. 

note 4 :

Dark-Blue ring with a white three alphanumeric code (on one leg) and metal ring (on other leg).

note 1 : two numeric and letter K that might be on positions : nKn, nnK, where "n" is a digit 0-9.

note 2 :

Dark-blue ring with a white three alpha code, starting letter "K" (on one leg) and metal ring (on other leg).

note 1 :

Orange ring with a black three alpha code, starting letter "K" (on one leg) and metal ring (on other leg).

note 1 :

White ring with a black three alpha-numeric code (on right leg) and metal ring (on left leg).

note 1 : birds ringed in The Netherlands.

note 2 : used codes are A00-A99 and 00A-99A.

note 3 :

Dark-green ring with white three alpha-numeric code.

note 1 : used codes are : A00-A99.

note 2 : birds ringed across The Solent, England.

note 3 : 

Yellow ring with black three alpha-numeric code.

note 1 : used codes are : A00-A99.

note 2 : birds ringed across The Solent, England.

note 3 : 

Black ring with a white three alpha-numeric code.

note 1 : used codes are :
letter 'T' - number - number  OR  number - letter 'T' - number  OR  number - number - letter 'T'.

note 2 : or another used code is : letter "M" / letter / number.

note 3 :