Terns

species: 
Common Tern
scientific name: 
Sterna hirundo
notes: 

White flag with a black four alpha-numeric code.

note 1 :

website sighting submit: 
Ornithological Station MIZ PAS
email sighting submit: 
colour-ring type: 
Flag : one, coded.
colour-ring colour (of the c-ring): 
White [W]
colour-ring code (of the c-ring): 
Four alpha-numeric code (4 letters/numbers).
countries where ringed: 
Poland.