Terns

species: 
Common Tern
scientific name: 
Sterna hirundo
notes: 

Yellow ring with a black three alpha-numeric code : 
* letter "Y" / number / number.
* number / letter "Y / number.
* number / number / letter "Y".

note 1 : some codes have used as first letter : N, P, R, or M followed by a letter and a number. These projects have not been agreed with the coordinator and may overlap with other cr-projects. 

note 2 :

email sighting submit: 
colour-ring type: 
Legring : one, coded.
colour-ring colour (of the c-ring): 
Yellow [Y]
colour-ring code (of the c-ring): 
Three alpha-numeric code (3 letters/numbers).
countries where ringed: 
Poland.