The leg bands are a form of identification for the bird. Prior to 1992, imported parrots and softbills had open stainless steel legbands placed on their leg which identified the birds that came through a certain quarnatine station. The U.S. D.A. agency required this identification. The bands had alpha and numeric data on them. The alpha, i.e., USDAM, indicated that the birds arrived into the Miami, Florida, quarantine station. the numbers, i.e., 0053, indicated a uniqure number for a particular bird in the shipment.
Aviculturists place closed aluminium or stainless steel bands on their birds for the following reasons:
Many organizations sell legbands to breeders with their own unique id, i.e., AFA "The American Federation of Aviculture," SPBE "The Society of Parrot Breeders and Exhibitors," NCS "National Cockatiel Society." These bands will also contain the breeder's information. Most of the organizations keep a database of bands sold so if a lost bird is found you could contact them for the breeder's information. Often times the breeders keeps a record of who purchased the bird and the bird may be reunited with its owner.