You will probably not be able to tell much from it unless you know who the breeder was. Breeders in the US aren't required to report to any kind of database nor use any standardized system for their bands. Typically their band codes are for their own records only. The only bands that can be traced are the old, open bands that were placed on legally wild caught birds who had been through quarantine before it became illegal to import them. Did your bird come from a pet store? They may be able to contact the breeder for you and get a hatch date. If not, you can consider the day you brought him home his "adoption day" or whatever you'd like to call it MANY bird owners have no idea when their birds were hatched and/or even a rough idea of how old they are.
Eclectus, CAG, BH Pionus, Maximilianâ€™s Pionus, Quakers, Indian Ringnecks, Green Cheeked Conures, Black Capped Conures, Cockatiels, Lovebirds, Budgies, Canaries, Diamond Doves, Zebra Finches, Society F
There is no national registry but typically sideways letters indicate state of origin, so chances are your bird came from Michigan. You can google green cheeked conure breeders in Michigan, and potentially track down the breeder who should be able to tell you the age of the bird based on the number. The letters are the breeder code. Another, less promising option is to start calling leg band companies. They cannot give out info without breeder consent, but some of us leave permission on file in case anyone tries to find out more about a bird that originates in our aviaries. This is particularly important to me, as my birds are all under a lease contract rather than sale, which means that if anyone sells them without my consent it is theft, so very much DO want to find out if one of my birds has been sold.