It's nice to hear about a bird finding a 'forever' home like this and you're right, it's important to have decent care early on.
When it comes to the band, though changes are trying to be made in the industry so that they're consistent and easily identifiable nationwide - that day isn't here yet.
Domestic birds wear closed bands. Their traceability depends upon the source of the band. Many bird associations such as SPBE, AFA or species related organizations offer record keeping services and bands to their members. There are other band providers who provide both traceable and non-traceable bands. To trace a band which has an organization name engraved on it, you would contact the organization engraved on the band. Each organization will have its own procedures to trace the band.
For example the bands for SPBE include a breeder code (usually 3 letters), a number (bird identification number) and the year. The initials SPBE also appear - that makes them traceable to that particular organization.
Major band providers, such as L & M Leg Bands and Red Bird, make many of the bands for the organizations mentioned. They also make bands for others, such as individual breeders and aviaries.
L & M offers customers engraving which includes: a buyer id code (up to three characters such as letters, numbers or symbols); a consecutive series of numbers so each band has a unique number for record-keeping; their state or Canadian province abbreviation; and lastly, the year. With the exception of some states, this is all optional. L & M is not imprinted on their bands.
It is difficult, and sometimes impossible, to trace a band which does not have an organization code on it.
The best course is to contact the major band manufacturers.
They have thousands of customers, so it is unlikely that the band buyer code would be unique. But they may be able to provide the names of a few breeders using this code, which is a starting point. The more information which has been engraved on the band, the better the chances of tracing it.
There are some states, such as Colorado or New Jersey, which have regulations which make tracing of bands easier. In Colorado the state assigns unique breeder codes that must appear on the bands, making them traceable. New Jersey requires band manufacturers to make sure that no one uses the same code twice and an 'NJ' in an oval must also appear on the bands. In California, budgies must have a traceable state registered closed band on in order to be sold, traded or bartered legally in the state.
You have a better chance at tracing the band by contacting all the vets that see birds in a tri-city or larger area and asking them.
Also, if this bird was ever seen by a vet, chances are the band was recorded in the record - so there may be an entire history out there.
When birds come to me after multiple pass-arounds I find bands simply missing. In many cases it's so the bird can never be traced, usually because a buyer has promised a breeder one thing and then done another. They don't want the bird finding their way back to the breeder and perhaps violating a contract.
Some breeders do this out of a sense of responsibility to the birds and I admire them for that. Unfortunately it doesn't always work.
I like that you've had a vet visit already - peraps a DNA profile done? Well worth it if not.
Every single new rescue I take has a DNA screen done.
This checks for several genetic diseases or other problems, as well as knowing for sure what sex your bird is (just in case you don’t know already). It’s something you can have done on your own, without a vet.
All it takes is a couple drops of blood that you might get by clipping a toenail just close enough to produce it (you need to be experienced with clipping and sure not to hurt your bird or cause severe bleeding).
I’d use a groomer or vet to get it if you’re even slightly unsure.
You can get an idea of the prices here http://healthgene.com/Avian and see that they’re pretty reasonable; however, again, I strongly recommend that your vet do the sampling, so figure in an office fee accessed along with the testing cost.
If you'd like to see more about how to integrate your new companion into your life, especially since he's a rescue, check this page 4AnimalCare
And whatever you might need - I'll do my best to help. I'm here every day, though the hours are different (I'm in California).
Thank you for saving this bird!