Common Tern
scientific name: 
Sterna hirundo

White (or yellow) ring with a black three alpha-numeric code.

note 1 : letter 'N' or 'H' on the first position OR letter 'N' on the 2nd or 3rd position (eg. 2NA or 2AN).

note 2 : the letter N or H is followed by one letter and one number (eg. NV2 or N2V) or by two numbers (eg. N42). 

note 3 : used letters are : A, C, F, H, K, L, N, P, R, S, T, V, X, Z. Used numbers are 1, 2, 3, 4, 5, 6, 7, 8, 9.

note 4 : IMPORTANT NOTICE: about 100 double codes starting with H (and followed by a letter and a number) were issued in 2019 by another project (https://www.cr-birding.org/node/5104). These differ in the presence of a dot after the H. Please when reading a white Common Tern CR with a H on the first position note if a dot is present in the code.

note 5 : a joint project of the Research Institute for Nature and Forest (INBO), Bureau Waardenburg and Ringgroup Delta.

note 6 : we use colour-rings in order to gain information on habitat use, juvenile dispersal, age of return and recruitment to the breeding colonies in the southwest of The Netherlands or beyond.

note 7 :

email sighting submit: 
colour-ring type: 
Legring : one, coded.
colour-ring colour (of the c-ring): 
White [W]
colour-ring code (of the c-ring): 
Three alpha-numeric code (3 letters/numbers).
countries where ringed: 
The Netherlands.
First letter/number (of the c-ring): 
N or H