For years I could count on at least a few birds hitting a window every spring. We already had the deflector stickers on the windows but they didn’t seem to work. I tried hanging a few other things in the window before discovering that I could bend some bamboo (from the back yard) into the window frame to hopefully create some awareness for the birds. It seems to have worked! On numerous occasions I’ve seen birds go into emergency stop mode as they neared the window. I’ve also seen them slow down but not in time enough to avoid a hit, but then be undamaged enough to fly off. If you’ve ever heard that tell-tale ‘thump’ against your window only to find a dying bird lying on the deck, then you’ll know what a relief it was to find something that helps.
Sometimes you can recover a stunned bird by gently holding it in your hands (for the warmth) until they come to.