Pigeon-proof cornice detail?

[Yikes]

For a new building in a historic area I'm looking for a precast concrete cornice (and water table) detail shape that would provide the necessary reveals when seen from below, but the top of it has enough slope to keep pigeons form roosting, without the use of additional spikes or wires. Is such a thing possible, or is this "unobtanium"?



In the example above, how steep would the red angled surface need to be in order to discourage roosting?
I don't have previous experience with this issue.

 

[cda]

I am thinking a lot steeper than that

 

[RLGA]

You might find this intersting...

https://core.ac.uk/download/pdf/159152875.pdf

 

[classicT]

https://core.ac.uk/download/pdf/159152875.pdf

Very interesting.

From the link Ron posted, "The maximum ledge width a pigeon is not able to sit on is 4 cm. The pigeon-safe angle of inclination for smooth construction materials (tinplate, glass, plastics) is 25°, for medium rough materials (wood, plane concrete) 35°, and for rough materials (sandstone, rough concrete) at least 50°."

 

[Yikes]

Thanks, that is very helpful!

 

[tbz]

I would contact the local bird sanctuary for better information