The British Trust for Ornithology (BTO) co-ordinate the bird ringing scheme for Britain and Ireland. Each year around 900,000 birds are ringed over 2,600 trained ringers. Ringing allows for the collection of scientific information on survival rates, productivity and bird movements. The rings are made from light weight metal, each inscribed with a unique number. These rings are placed around the bird’s leg which is completely harmless and does not affect the bird in any way.
“Ringing allows us to study how many young birds leave the nest and survive to become adults, as well as how many adults survive the stresses of breeding, migration and severe weather. Changes in survival rates and other aspects of birds’ biology help us to understand the causes of population declines.” BTO website
Birds are caught using mist nest, a type of fine mesh net between two poles. The birds fly into these nets and become trapped. They are safely removed by trained ringers who apply the ring and take weights and measurements from the birds. Chicks are also ringed in the nest.
Other types of rings used are colour rings. These can be on the legs (often seen on wading birds) or around the neck of larger birds (geese and swans) the colour combinations and/or numbers can usually be read through binoculars or a scope. There is a Greylag goose frequently seen around the south end of Shetland with this type of neck ring.
What to do if you find a bird with a ring
You can report metal and colour rings through the BTOs reporting website here
Metal rings can be near impossible to read on a healthy bird. Most rings found by the general public are from dead, injured or trapped birds. (The BTO themselves do co-ordinate re-capture projects where ring numbers and measurements are taken and the bird is released). BTO rings and colour rings, as well as rings from other institutions throughout Europe can be reported to this website just follow the onscreen instructions.