My father-in-law lives in a 3rd floor apartment with a small balcony,
in a city suburb. Unfortunately the balcony suffers from the visits of
numerous pigeons which leave their droppings everywhere.

He has tried shiny tape along the balustrade and various arrangments
of coloured string tied from the top of the sliding windows to the
balustrade. All of which are not very good at deterring the pigeons,
and also unsightly in themselves.

Has anyone got any better ideas (other than buying him an air rifle,
which given the infinite number of birds would be impractical and
attract comments from the RSPB etc)?

Pete