Try to find a local wildlife rehabilitator. If you don't see one listed in the phone book, ask your nearest humane society. They should be able to help you get in touch with someone who could creatively rescue the bird. When this happened to me about 10 years ago, I left the windows open in the basement, and blocked off all the other windows (that couldn't be opened) and the trade-off of a few bugs was worth the bird figuring out where the fresh air was coming from, and leaving. Maybe climate doesn't allow for that right now, depending on where you are.