A lot of people post them on craigslist.org or similar under the "free" or "farm & garden" sections of my local area, hopeful that someone outside of the city ordinances will take them to loving forever homes. I have gotten a few this way, but I live out in the boonies, where ordinances don't exist!
So, I often rescue birds trapped in hard places like that. I am sure there are similar people in your area, as well.