Swans

species: 
Mute Swan
scientific name: 
Cygnus olor
notes: 

Dark-green neckband with a white four alpha-numeric code, starting letter 'BG' followed by two numbers.

note 1 :

email sighting submit: 
colour-ring type: 
Neckband.
colour-ring colour (of the c-ring): 
Dark Green [G]
colour-ring code (of the c-ring): 
Four alpha-numeric code (4 letters/numbers).
countries where ringed: 
Bulgaria.
First letter/number (of the c-ring): 
BG