Each year in the United States, nearly one billion birds die after colliding with glass. Collisions often occur because windows reflect foliage or sky, which looks inviting for the bird to fly into. The good news is that there are a few simple things you can do to prevent birds from colliding with your windows.

How to make your windows bird-friendly.

1. Install window screens to obscure reflections and provide a visual barrier for birds. 
2. Paint your windows with tempera paint in a grid pattern of 2 by 2 inches or paint your own art on your window. 
3. Apply window decals to the exterior of the window and space them close together. For example, Feather Friendly makes an adhesive dot pattern. 
4. Install a parachute cord, which are closely spaced ropes that hang down over windows. Acopian Bird Savers are premade versions used by the Cornell Lab of Ornithology. You can also make your own DIY parachute cord. 

Tips to remember.

1. Go outside and identify windows that could be dangerous to birds. Look at windows from different angles throughout different times of the day from a bird’s point of view. If you see vegetation or sky reflected in the glass, a bird will see that too.  
2. Vertical markings on windows should be spaced on a 2-inch by 2-inch grid to prevent collisions by small birds such as hummingbirds, kinglets, and siskins.  
3. Paint and decals should use high contrast colors in order to be visible to birds.

Information from the Cornell Lab of Ornithology and NYC Audobon.