The band is primarily for the breeder. After that, it doesn't really matter.
Your bird also needs a band or microchip to cross into other countries. For smaller birds that may be ineligible for microchips, bands do serve a purpose.
Yeah pretty much my point they are useless except in helping a breeder to tell similar colored baby birds apart from another, especially ones that DNA sex their birds, and a customer wants a specific sex.
I would think that Green cheek conures are a bit to small for a microchip. Plus I don't have any plans of ever leaving the country, as I don't possess the ammount of money required for an exotic/foreign vacation or trip.
There is a small about 5-10% chance it'll be found & the chip can get it back to you.
While I do agree a chip would help get a bird back to you, because the chip can be scanned, which is programed with your information in order to get the bird back to you.
However, a band does not fulfill the same roll as a chip, because it doesn't have any imbedded information about you, and as we've already discussed there is virtually no where to even look up the band numbers to get information about the bird the band is attached to, or the birds owners either. So anyone who finds the bird would be in exactly the same place I am now, unable to find any information about the bird, who the breeder was, where it was bred, it's current or previous owners names, nothing.
Also on that note my bird is a green cheek conure, which I believe is far to small for a chip, and even if there was a chip small enough to not hurt my bird, I probably wouldn't put it in my bird anyway.
Also, there are certain times a band can help. I believe when being checked by a vet to verify that it IS actually your bird, when crossing into states or driving thru states where certain parrots are illegal to own.
I do live in the United States, and it is my understanding that in other countries this is less of an issue as some do have centralized databases where a birds leg band can be typed in, and information about the bird, and it's owner can be found.
However here in the United States no such thing exists. Someone previously linked to a database they maintained I believe, but you have to know what state the bird was bred in, and if you don't then your out of luck, and even though I'm fairly certain my bird was bred in my state, I tried my state and every surrounding state and no information was found.
So my point is here in the USA leg bands are useless except to a breeder. You would think that the united state wildlife agency or something would have a central database where you can register you birds leg band and your information, and update it as needed so that if your bird does fly out the window the leg band will actually serve the purpose it was meant to fulfill.
Also based on information I could find Green Cheek Conures aren't banned, or restricted anywhere in the USA.