you got to teach them when very young first time on the roof chase them off second time do the same and so on they soon realise that their not allowed on the roof , my loft is in a bit with houses all round them and they drop right onto loft from exercise training or racing, as thats what their trained to do , and joe nearly 62 i throw tennis balls at them until they know how is the boss what i say goes , and they still win well for me and trap as if the landing board is on fire.A member of my old club used to say to me every time my birds home from a race they just perch on the roof (if you drove by any day of the week there they would be sitting on the roof )i said to him in my usual manner no bloody wonder they think thats their perch because the spend more time on the roof than they do in the loft ya eijit. UNDER CONTROL IS THE NAME OF THE GAME