Gulls

species: 
Great Black-backed Gull
scientific name: 
Larus marinus
notes: 

Black ring with a white four alpha code, starting letter "G", followed colon ":"

note 1 : the project runs in Gipuzkoa, Spain but also in Bizkaia.

note 2 :

website sighting submit: 
Aranzadi Portal for special marks in birds.
email sighting submit: 
colour-ring type: 
Legring : one, coded.
colour-ring colour (of the c-ring): 
Black (Niger) [N]
colour-ring code (of the c-ring): 
Four alpha code (4 letters).
colour-ring position (of the c-ring): 
Tarsus right.
countries where ringed: 
Spain.
First letter/number (of the c-ring): 
G