Hi all,
We have an issue with birds nesting in the gap under out balcony above our columns. Due to the rounded shape of the columns we're not exactly sure the best way to tackle the problem.
Here's a picture of the nest and the size of the gap we're dealing with.

Ideally we would do something that completely plugs the gap, and remains flush to the outside of the column. Does anyone have a solution they could recommend?
Here are some more pictures:


Any ideas are appreciated. Thank you.