The rings

The absolute must for ringing is to use the right ring size and type. In Finland, there are a total of 26 ring sizes of differing diameter in use, but the different ring types (used in Finland) amount to 36. Most rings are made from aluminium. Steel and even harder alloys are used only for such bird species (e.g. auks and gulls), on whose legs an aluminium ring would last only for a few years.

In addition to the return address all rings are engraved with an individual marking (the number of the ring). The marking includes no more than two letters - and these define the type of ring - the rest are running numbers. The numbers of the ring can be for instance like these: X123456, 123456J, PA12345, HT- 123.456, EJ1234

The return address has been printed in its Latin form on Finnish rings. Thus, instead of "zoological museum" the largest rings say MUSEUM ZOOLOG, HELSINKI, FINLAND or MUS.ZOOL, HELSINKI, FINLAND, whereas the smallest rings contain only the following: MUS.Z.HKI, FINLAND.

Of the rings, the smallest fits a Goldcrest, the largest a Mute Swan. The diameter of a ring for a Goldcrest is 1.8 mm, the weight only 0.03 g. The corresponding measurements for a ring for a Mute Swan are 26 mm and 12 g. The Goldcrest itself weighs on average 5.5 g and the Mute Swan up to 15 kg. Thus, the weight increase to the bird from the ring can be roughly compared to that of a wristwatch for a human. In addition to the metal ring, birds can, in special studies and by a separate permit, be fitted with extra identifiers such as coloured leg or neck rings.