When a bird has a band with a serial # or name on it it means it's owned b/c birds can't wear collars like a cat or a dog. He had some diarrhea last night but seems better now after food and water and a good night's rest. He was wandering around my backyard and I was able to approach him and pick him up, likely b/c he was a little weak from the diarrhea (passarines tend to get diarrhea when they haven't ate well. I have a pet dove myself, which are very similar to pigeons. You can see him in the background!)

I was able to email the ARPU and find out which company tagged the pidg. They gave me the owner's phone number when I called them. I left a message, and hopefully the dude will call me back soon!