There a re a lot of pigeons on my roof and now is full of **** what can i do to make them go away?

i want to find a way to make the pigeons go away of my roof they are always trowing their poop on it and at 5 or 6 am thie sound will not let me sleep i got tired of them and sometimes i even throw trhem rocks butr they will always come back i i'm sick and tired about this and i want to find a wa to make them go away and never come back