What is bird banding?

Bird banding is a research method that attaches individually identifiable markers, such as leg bands and neck bands, to birds. Information such as migration routes and longevity are gained when released birds are later recaptured or observed.
Basically, the procedure involves attaching a metal leg band engraved with a serial number. Other marks, including neck bands, color flags, or tags, may also be used for certain species or groups.
When a banded bird is photographed, captured alive or found dead (some may die from accidents or from a natural death and their bodies are collected), information regarding species, date, place of release, sex, and age can be identified from the serial number on the band.
This research method began about a century ago in Europe and is now popular in about 34 countries worldwide.