Bird-of-prey silhouettes and similar window stickers are ineffective at preventing collisions, at least when applied in the way most people do, as in the first illustration.1
If you apply a few stickers to the window, birds will simply try to fly around them and still hit the glass.
Nor do bird-of-prey stickers scare birds away from windows.
That’s not to say stickers can’t be effective.
To meet the criteria for effective window markers, you would need to apply many more of this type of sticker, as in the second illustration.
That would your view out the window!
Luckily there are better solutions.
- Trybus, T. 2003. Wirksamkeit von Greifvogelsilhouetten zur Verhinderung von Kleinvogelanprall an
Glasfronten. Die These des Masters, der Universität Wien ↩︎