A:https://www.bird-x.com/images/Spikes-Polycarbonate-regular.jpg Joan, The most effective method is to install these devices called bird or pigeon spikes. The name sounds horrible, but they are actually very humane. They repel the potential perchers without injuring them. Even the American Humane Society endorses them. The only drawback, IMO, is that they are unsightly. I hope this helps.
