how is bird ringing done?

Leg ring

A bird is ringed with a lightweight strip of aluminium, wrapped loosely around one of its legs. The band weighs less than a half-percent of the bird's body weight.

Normal life

Even with a ring on its leg, the bird is able to move normally. This is important for both ethical and scientific reasons; ringing birds would not yield any meaningful results if it interfered with their normal function.

Unique number

All bird ringing in Sweden is administered by Bird Ringing Centre at the Swedish Museum of Natural History. Every ring has its own special number. Also engraved is the name and address of the museum.