Be gone, birdies!

Does anyone know a humane way to get birds out of the walls of your house? I was planning on plugging up the hole (I believe it was initially made to put insulation in the walls) when they left for the winter, but the tenacious little fuckers never went anywhere (and why would they with such a warm cozy home?). I really don't want to trap them in there, but am not sure what to do. Although I have to admit, after reading a graphic novel that talked about starlings...I have to say if that is what they are I wouldn't feel so bad.