My vet has told me that if I want to get either my B&G or CAG banded he would do it for me. Of course it would be just for ID purposes (he breeds birds). Also don't forget birds can be micro chipped too like dogs.

The main purpose of banding (besides ID) is to prove a bird is not wild caught. Some wild birds are still smuggled in from Mexico. To prove a bird is captive bred, they would have a closed band put around their leg when they were babies, while it could still slide over the foot. There's really no point to banding an adult - only an open band could be put on and there is always a small risk of a bird snagging a band on a toy and injuring its leg. The microchip is a better idea for medium and large birds.
Some breeders don't band their birds at all, and some do but suggest owners have it removed by their vet later... neither of mine were ever banded.

Karen
Chico (conure) and Pippin (budgie)
WI

I just bought my bird from a breeder here in Kentucky, and he/she didnt have a band either. she gave me proof of purchase with a certificate.