Terns

species: 
Black Tern
scientific name: 
Chlidonias niger
notes: 

Dark green flag with a white three alpha code.

note 1 : used letters as first letter : A, B, C, E, F and H .

note 2 : 

website sighting submit: 
Ornithological Station, Museum and Institute of Zoology of the Polish Academy of Sciences.
email sighting submit: 
colour-ring type: 
Flag : one, coded.
colour-ring colour (of the c-ring): 
Dark Green [G]
colour-ring code (of the c-ring): 
Three alpha code (3 letters).
countries where ringed: 
Poland.