you can also put (bird) stickers on them, so they see the window and they avoid it
The window has too nice a view to ruin unfortunately.
Bird stickers unfortunately don't work, birds don't recognize them. Something like "anti collision dot stickers" will work though if the spacing between the dots is not larger than recommended.
Bird eyes are more sensitive to UV light than humans right? Better UV reflective coating would help them?
Or a transparent film with a pattern of absorbed and reflected UV?