Those plastic owls or birds of prey you can use to stop pigeons from perching on - in my case, the pipes on the outside of my house, do they work? Are they an effective deterant? thanks
They may work in the short term but I bet you'd find the pigeons pecking, sitting on and using it as a toilet in a very short space of time. If you contact yoru local council they may know of an effective deterrent.
When Ken Livingstone banned people from feeding pigeons in Trafalgar Square, a falconer was introduced to deter the pigeons from landing there. I often saw the falconer, with a bird of prey on his wrist, standing in the Square while pigeons landed at his feet and on the walls around him, only a few feet away from the falcon. If pigeons aren't deterred by a live predator, I doubt that there's much chance that they'll be bothered by a fake one.
I went to a flat once to judge a gardening comp - it was near Trafalgar Sq and it was on the roof of a block of flats - they had one of those plastic birds (I can't remember which one tho) and said it had been keeping all the pigeons away since they put it up.