Bird ringing or bird banding is the attachment of a small, individually numbered metal or plastic tag to the leg or wing of a wild bird to enable individual identification. This helps in keeping track of the movements of the bird and its life history. It is common to take measurements and examine conditions of feather molt, subcutaneous fat, age indications and sex during capture for ringing. The subsequent recapture or recovery of the bird can provide information on migration, longevity, mortality, population, territoriality, feeding behavior, and other aspects that are studied by ornithologists. Other methods of marking birds may also be used to allow for field based identification that does not require capture.
The earliest recorded attempts to mark birds were made by Roman soldiers. One instance occurred during the Punic Wars: In 218 BC a crow was released by a besieged garrison (which suggests that this was an established practice). Quintus Fabius Pictor used a thread on the bird's leg to send a message back. In another instance, a knight interested in chariot races during the time of Pliny (AD 1) took crows to Volterra, 135 miles (217 km) away and released them with information on the race winners.
Falconers in the Middle Ages would fit plates on their falcons with seals of their owners. From around 1560 or so, swans were marked with a swan mark, a nick on the bill.
Storks injured by arrows (termed as pfeilstorch in German) traceable to African tribes were found in Germany in 1822 and constituted some of the earliest evidence of long distance migration in European birds.
In North America John James Audubon and Ernest Thompson Seton were pioneers although their method of marking birds was different from modern ringing. In order to determine if the same bird would return to his farm, Audubon tied silver threads onto the legs of young eastern phoebes in 1803, while Seton marked snow buntings in Manitoba with ink in 1882. Ringing of birds for more extensive scientific purposes was started in 1899 by Hans Christian Cornelius Mortensen, a Danish schoolteacher, using aluminum rings on European starlings (Mortensen had tried using zinc rings as early as 1890 but found these were too heavy). The first banding scheme was established in Germany by Johannes Thienemann in 1903 at the Rossitten Bird Observatory on the Baltic Coast of East Prussia. This was followed by Hungary in 1908, Great Britain in 1909 (by Arthur Landsborough Thomson in Aberdeen and Harry Witherby in England), Yugoslavia in 1910 and the Scandinavian countries between 1911 and 1914.Paul Bartsch of the Smithsonian Institution is credited with the first modern banding in the U.S.: he banded 23 black-crowned night herons in 1902.Leon J. Cole of the University of Wisconsin founded the American Bird Banding Association in 1909; this organization oversaw banding until the establishment of federal programs in the U.S. (1920) and Canada (1923) pursuant to the Migratory Bird Treaty of 1918.