I used the 22 CB's to clean the pigeons out of the loft of our dairy barn. They got smart enough to not fly out no matter how much commotion you made. The CB's wouldn't penetrate the pine boards the barn is sided with, but would kill a pigeon. After I got the last one, none came back. Someone on here has mentioned that a bird wants to roost where it was hatched, my experience would lend credence to that theory.