Terns

Combination of 2 metal rings, one on each tarsus, consisting of an engraved coded metal ring and the regular metal ring.

note 1 : ‘Roseate Specials’ is the type of rings used for this species in virtually all parts of the world away from the Pacific. The term applies to ‘field readable metal rings/bands’ that are put on whichever tarsus does not carry the national ring.

The vast majority are ringed this way as chicks. The Australians (and maybe Japanese) have their own scheme and can use wader-style colour darvic flags.
The Roseate Special scheme is used by the USA, Canada, all Europe (including the Azores) and on Aride in the Seychelles (David Monticelli can advise on this).
The photo shows a typical bird : the 4-digit code is repeated twice (three times on some very old birds) and should be read as the top two numbers/letters and then the bottom two. Hence the code of this bird is 21R1. To date all rings have a single letter and 3 numbers [though we are likely to start using number-number-letter-letter sequences in summer 2010 (e.g. 21RR)].
The only other tern ringing scheme that uses this type of ring is in Canada where they fit them to Arctic Terns in a letter-letter-number-number sequence. We will not repeat these sequences on Roseate Terns.

note 2 : using all letters and also the registration www.ring.ac address.

note 3 :