Common Tern

Yellow ring with a black 3 alpha-numeric code : letter U followed by 2 numbers (on left leg) and metal ring (on right leg).

note 1 : birds ringed in Leicestershire, UK.

note 2 : used codes are U01-U99.

note 3 : birds ringed during 2017.

note 4 :

White ring with a black three alpha-numeric code (project-letter 'K', can be at any position.)

note 1 : used positions : Knn, nKn, nnK where 'n' is a number from 0-9.

note 2 : during 2021 the code : "letter 'K' / letter / number was used.

note 3 : 

Dark-blue ring with a white three alpha-numeric code, starting-letter 'G'.

note 1 :

Red ring with a white three alpha-numeric code, starting-letter 'G'.

note 1 :

Yellow ring with a black three alpha-numeric code, starting-letter 'G'.

note 1 :  G00-G99, GAA-GZZ, GA0-GZ9 and G0A-G9Z

note 2 :

Black ring with a white three alpha-numeric code, starting-letter G.

note 1 :  

Green ring with a white three alpha-numeric code, starting-letter 'G'.

note 1 :

White ring with a black three alpha-numeric code, starting-letter 'G'.

note 1 :

Dark-blue ring with a white three alpha-numeric code, starting letter "I".

note 1 :

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

note 1 :  used codes are : 
letter "M" / letter / number.

note 2 : used codes are :
letter "Y" / number / number
number / letter "Y / number
number / number / letter "Y"

note 3 :