Great Black-backed Gull

Orange ring with a black four alpha-numeric code :
starting letter 'F' / : / letter / number / number.

note 1 : used codes are F:A01, F:A02, ... F:Z00, F:Z99.

Black ring with 3 alpha-numeric code.

note 1: used codes are : three letters (E, J, K, L, M, P) or numbers (00 till 99).

Yellow ring with a black four alpha-numeric code , starting letter "B" followed by a colon ":" and three numbers.

note 1 :

Dark-green ring with a white four alpha-numeric code (on left tarsus) and metal ring (on right tarsus).

note 1 : starting code is letter "B:" (note the colon) followed by three numbers.

note 2 : 

Yellow with a black four alpha-numeric code : number , number , number , colon ":" letter M (on one leg) and metal ring (on other leg).

note 1 : codes are 000:M to 999:M

note 2 : used codes :

2018 : 065:M to 117:M.

2019 : 000:M, 001:M, 121:M to 132:M, 135:M, 136:M, 139:M, 140:M, 142:M,

145:M to 147:M, 150:M, 151:M, 156:M to 162:M.

2020 : 133:M, 134:M, 137:M, 144:M, 152:M, 163:M to 169:M, 174:M to 178:M

note 3 :

Red ring with a white four alpha-numeric code :
- number / number / number / ":"/ letter 'D' (on  left tarsus).
- letter / number / number / ":"/ letter 'D' (on  left tarsus).
- number / letter / number / ":"/ letter 'D' (on  left tarsus).

note 1 : some 200 birds HG/LBbG/GBbG are ringed in Dublin during 2017.

note 2 : 

Black ring with a white four-alpha numeric code : nxxn, where n is a number and x a letter.

note 1 : birds ringed on Guernsey.

note 2 : 

Yellow ring with a black four alpha-numeric code,
*starting letter "T" followed by three numbers.
* starting letter "X" followed by three numbers.

note 1 : used codes are : T:041-T:080 ; X:001-X:032.

note 2 : this project is a not-agreed one.

note 3 :  

Black ring with a white four alpha-numeric code, starting letter "X".

note 1 :

Yellow ring with a black four alpha-numeric code, starting letter 'C'.

note 1 : up to 2014, a total of 8 rings delivered since 1996.

note 2 :