hey wiresoma, basically there are 2 band types used here in the US. Open band ( has a "joint" in the band) and a closed ring (with no joint) .Closed ring can only be placed on a bird when it is less than about 12 days old. Open rings can be put on by anyone at any time. MOST open bands used here in the US where used by the USFWS to band imported birds that had survived USFWS 90 day Quarantine. This bands have USDA and a code on them. The code tells you what Quarantine station they passed thru (survived). Some have a usable date but you can get no other info from USDA/USFWS other than the year and what quarantine station. I dare you to get on the phone and try to get some info from Uncle Sam about your birds import band. Enough. Open bands mean very little and are proof of very little. If it's bothering your bird have it removed. I think you said your bird was about 5 yrs old, a immature zon, they still play a lot at that age and just "beaking" a closed ring type band wouldn't worry me. UNLESS it was too tight (like your zon is getting fat?). Closed Ring, I'd leave, Open Band ,i'd tend to cut off, mirco-chip instead.