Here is a one page instructional guide on how to read coloured bird bands. Band observations should be sent to bandingoffice@doc.govt.nz. Many birds now have ELFs (Engraved Leg Flags) sightings of ELFs on New Zealand dotterel (even if you can not read the letters on the flag) should also be sent to the Department of Conservation banding office.
Additional notes for Tara iti / NZ Fairy tern (2024):
B = Blue (blue can fade to gray)
K = Black
M = Metal
pG = Pale green
L = Lime green