Nearly half of all window strikes happen at houses. That’s why it’s so important that you do what you can to make your viewing area safe for birds. Your strike-proofing project need not break the bank—plenty of DIY solutions will make your windows safe.
Move bird feeders and birdbaths at least 30 feet away from windows, or up close to windows (less than 3 feet away).
Relocate large houseplants away from windows where birds often collide with the glass.
Apply decals to the outside of windows—but lots of them, no more than 4 inches apart.
Apply a window film with a pattern to the outside of the window. CollidEscape or Solyx offer some good solutions.
Apply netting, bird screens, hanging strips, or other products over the outside of the window.  Options include Acopian BirdSavers, PollyNet bird netting, and others
Shades that roll down over the window also help reduce collisions, by making the window look solid to birds.