Sandwich Tern

Dark-green ring with a white three alpha-numeric code and metal ring (on other tarsus) :
*starting letter "N" or "J" or "H" / number or letter / number or letter.

note 1 : Always letter 'N' on first position; followed by one letter and one numeric (e.g. NV2 or N2V); or one numeric and one numeric (e.g. N12); or one letter and one letter (e.g. NVT)

note 2 : Always letter ‘H’ on first position; followed by one letter and one numeric (e.g. HV2 or H2V); or one numeric and one numeric (e.g. H12)

note 3 : Always letter ‘J' on first position, followed by one numeric and one numeric (e.g. J12); or one letter and one numeric and a ‘.' [dot] in the code in a random position (either between first and second digit, or between second and third) (e.g. J.2T or J2.V); or one letter and one letter (e.g. JVT)

note 4: The letter 'N' on various positions in the code, always starting with a numeric and followed by a letter (e.g. 2NC) or starting with numeric and numeric followed by N (e.g. 23N).

note 5 : a joint project of the Research Institute for Nature and Forest/INBO, Bureau Waardenburg and Ringgroup Delta. This project started in 2010 and each year (except in 2011) both adults and juveniles have been colourringed.

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

note 7 : used letters are : A, C, F, H, K, L, N, P, R, S, T, V, X, Z.

note 8 :

Dark-green ring with a white three alpha code and metal ring (on other tarsus) : starting letter "N" , "J" or "H" / letter / letter.

note 1 : Always letter 'N' on first position; followed by one letter and one numeric (e.g. NV2 or N2V); or one numeric and one numeric (e.g. N12); or one letter and one letter (e.g. NVT)

note 2 : Always letter ‘H’ on first position; followed by one letter and one numeric (e.g. HV2 or H2V); or one numeric and one numeric (e.g. H12); or one letter and one letter (e.g. HVT)

note 3 : Always letter ‘J' on first position, followed by one numeric and one numeric (e.g. J12); or one letter and one numeric and a ‘.' [dot] in the code in a random position (either between first and second digit, or between second and third) (e.g. J.2T or J2.V); or one letter and one letter (e.g. JVT)

note 4: The letter 'N' on various positions in the code, always starting with a numeric and followed by a letter (e.g. 2NC) or starting with numeric and numeric followed by N (e.g. 23N).

note 5 : Always numeric ‘2' on first position and a ‘.' [dot] in the code in a random position (either between first and second digit, or between second and third); followed by one numeric and one numeric (e.g. 2.25); or one letter and one numeric  (e.g. 2.2T or 22.V); or one letter and one letter (e.g. 2.VT or 2V.T)

note 6 : a joint project of the Research Institute for Nature and Forest/INBO, Bureau Waardenburg and Ringgroup Delta. This project started in 2010 and each year (except in 2011) both adults and juveniles have been colourringed.

note 7 : we use colour-rings in order to gain information on migration, habitat use, juvenile dispersal, age of return and recruitment to the breeding colonies in the southwest of The Netherlands or beyond.

note 8 : used letters are : A, C, F, H, K, L, N, P, R, S, T, V, X, Z.

note 9 :

Dark blue ring with a white three alpha-numeric code, starting letter 'K' (on left leg) and metal ring (on right leg).

note 1 : birds ringed in Norfolk, UK.

note 2 :

Orange ring with a black three numeric code (on one leg) and metal ring (on other leg).

note 1 : used codes 000- 999.

note 2 :

Red ring with a white three alpha-numeric code, starting letter 'T' followed by two numbers (on left leg) and metal ring (on right leg).

note 1 : used codes are T00-T99, 0T0-9T9, 00T-99T.

note 2 : 

Red ring with a white three alpha-numeric code, letter 'T' can be on first, second or third place and two numbers (on left leg) and metal ring (on right leg).

note 1 : used codes are T00-T99, 0T9-9T9, 00T-99T.

note 2 :

Dark green ring with a white three alpha-numeric code, starting letter "L" (on one leg) and metal ring (on the other leg).

note 1 : the project started in 2024.

note 2 : used letters are : A, C, E, H, J, K, L, N, P, R, S, T, U, V.

note 3 : the rings are used on both nestlings and adults.

note 4 :

Dark green ring with a white three alpha code, starting letter "L" (on one leg) and metal ring (on the other leg).

note 1 : the project started in 2024.

note 2 : used letters are : A, C, E, H, J, K, L, N, P, R, S, T, U, V.

note 3 : the rings are used on both nestlings and adults.

note 4 :

White ring with a black three numeric code (on one leg) and metal ring (on the other leg).

note 1 : the project started 2024.

note 2 : used codes are 751-999.

note 3 : birds were ringed on Hallig Norderoog, Germany.

note 4 : the rings are used on both nestlings and breeding adults.

note 5 :

Yellow ring with a black symbol '+' and a two alpha code.

note 1 : used code is : +/letter/ letter.

note 2 :