Gulls

species: 
Black-headed Gull
scientific name: 
Chroicocephalus ridibundus
notes: 

Yellow ring with a black four alpha code, starting letter 'T'.

note 1 :

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 code (4 letters).
countries where ringed: 
Poland.
First letter/number (of the c-ring): 
T