The problem is when the chicks are born the adults throw all the bird poo out of the nests to the floor below which causes insect to be attracted to it and in Turkey cockroaches. I remember my parents getting these birds nesting right under there front door, what a mess they made and people had to run in and out for fear of being dive bombed. Next year, as soon as they started to build again, my Father went out with the hose.
The stuff we have outside is a transparent gel which is called Bird Proof. However, there are lots of these products under different brand names on the net.