I did some searching on yellow bands and it looks like they're pretty commonly used on homing pigeons. So likely it's an escapee from someone's coop and/or its homing instinct failed.
Maybe it will find its way home. Or maybe its found love in your local flock and will stick around for a while!
"We are--each of us--dying; it's how we live in the meantime that makes the difference."
"It's not what you gather, but what you scatter that tells what kind of life you have lived!"
"Be kinder than necessary, for everyone you meet is fighting some kind of battle."