Hi Karenr,
There is a gel you can get and apply to the wall, birds feel uncomfortable landing on it and will fly away.
We got my daughter some a few years ago when she lived in a flat and was troubled with pigeons on the window sills. However, not sure if it will stick on a wall. I think we have some outside, will check if it's there and tell you the name on it and I will read the instructions. Perhaps they sell it in Turkey... Will post again tomorrow.