I had birds build a nest in a nook where I put the spikes going up and down like stalactites and stalagmites. They didn’t care and built right in the middle of the spikes… will look at just boarding up the nook next year I guess.
It was explained in the original Dutch video that birds choose to build a nest under the spikes, because it protects them from other animals trying to steal their eggs.
This sort of happens in the wild too. Weaverbirds spend their life on spiny trees and build their nests on branches of such spiny trees.