I've been using the transparent maple leaf shaped Ultraviolet reflecting stickers now for over 12 months and have had no known bird strikes since applying them to the windows, I used quite a few. My friend took a pack and still had a couple of strikes, but then I noticed that he had put them on the inside, he has now moved tham and has had no more strikes.
The window cleaner has no problems with them by the way.
I did get a pack of the spider web ones as well, but found that with time the webs would generate naturally.
