For folks at home thinking about their windows: Apparently one issue is that windows may mirror the outside environment to birds, appearing as portals to more open-space and trees, especially if you include ultraviolet light which humans can't see and which the glass wasn't designed to pass-through.
So there are a variety of products advertised for home usage that stick to the outside of the window to make it appear more like a barrier, often semi-transparent to us but more-opaque in ultraviolet to birds.
That evening, the Roly-Poly Bird flew round and round The Big Red House singing out,
"There's sticky dirt stuff all over the pane!
If you fly at the surface, you'll damage your brain!
So fly away! Fly away! Do not crash!
Or you'll finish up tomorrow in a cold Bird Mash!"
So there are a variety of products advertised for home usage that stick to the outside of the window to make it appear more like a barrier, often semi-transparent to us but more-opaque in ultraviolet to birds.