Gulls.

species: 
Eurasian Mew Gull
scientific name: 
Larus canus
notes: 

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

note 1 : up to 2014, a total of 50 rings were delivered since 2002.

note 2 :

website sighting submit: 
Report form for Finnish ring recoveries.
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): 
Four alpha-numeric code (4 letters/numbers).
countries where ringed: 
Finland.
First letter/number (of the c-ring): 
C