How to reduce bird-glass collisions

  1. Use external window screens.1 When birds fly into screens as opposed to glass, it serves to cushion them and should not result in injury.
  2. Use shutters, blinds, and curtains to reduce window strikes. Closing interior window coverings is only useful when windows receive direct sunlight—only then do birds see shutters and curtains instead of mirrored reflections caused by bright light on the outside of glass and low light on the inside of glass.2 Light-colored shutters and curtains are thought to work best.8
  3. Move bird feeders and birdbaths closer to or further away from windows. For example, feeders and other bird attractants should be within 3 ft. of glass4 or 30 ft. or more from glass.5 Close enough distances prevent birds from gaining enough speed and hitting windows hard enough to result in fatal injuries. Birds will slow down to stop at bird attractors, but can be startled at takeoff and fly into a window accidentally. Placing bird attractors at far distances from glass, on the other hand, prevents birds from getting close enough to windows and should altogether prevent injuries. Cost: $0
  4. Reduce the number of indoor plants near windows.3,4 As a rule, vegetation inside of buildings should not be visible from outside when looking through transparent glass. Cost: $0
  5. Apply closely spaced decals or tape strips to your windows to alert birds to barriers. These should be placed 2 inches apart or less when the strips run horizontally, and 4 inches apart or less when they run vertically.5 The shape of decals does not matter; it is more important that the decals follow the 2×4 rule. Making your windows bird-safe can also be a family activity! You can create your own decals with tools found on art supply websites such as and Cost: $1115
  6. Fashion netting to your storm windows so that birds have a soft landing. The best type of netting to use has smaller-spaced mesh of 5/8″ diameter cropped like this.6 This way, the impact netting itself does not become hazardous to birds. Cost: $13–50
  7. You can also use screens to deflect birds.
  8. Hang darkly colored 1/8″ parachute cord spaced out 10.8 cm (4 ¼ in.) or 8.9 cm (3 ½ in.) in front of clear and reflective windows7 to make “Zen window curtains” (or purchase them here). While the cords do not have to be attached at the bottom, you can attach them to the top of your window frame with an aluminum support strip and Velcro, aluminum tabs, or molding with drilled holes and wire loops. If you have additional questions after referencing this site, please contact Matt Webb. Cost: $20–51
  9. Apply bird collision prevention film over windows through the company CollidEscape. Choose from white, clear, tinted, imaged, or dots, patterns, stripes, and shape-cut. Cost: $34–147
  10. Install non-reflective tinted glass.7 Cost: $900–2,500


1 Hager, Stephen B., Heidi Trudell, Kelly J. McKay, Stephanie M. Crandall, and Lance Mayer. “Bird Density and Mortality at Windows.” The Wilson Journal of Ornithology 120.3 (2008): 550-564. Web. 6 Aug. 2014.

2 Hager, Steven B., Bradley J. Cosentino, Kelly J. McKay, Cathleen Monson, Walt Zuurdeeg, and Brian Blevins. “Window Area and Development Drive Spatial Variation in Bird-Window Collisions in an Urban Landscape.” Plos One 8.1 2013: 1-10. Web. 6 Aug. 2014.

3 Loss, Scott R., Tom Will, Sara S. Loss, and Peter P. Marra. “Bird-building Collisions in the United States: Estimates of Annual Mortality and Species Vulnerability.” The Condor 116.1 (2014): 8-23. Web. 6 Aug. 2014.

4 Gelb, Yigal and Nicole Delacretaz. “Windows and Vegetation: Primary Factors in Manhattan Bird Collisions.” Northeastern Naturalist 16.3 2009: 455-470. Web. 6 Aug. 2014.

5 Klem, Jr., Daniel. “Collisions Between Birds and Windows: Mortality and Prevention.” Journal of Field Ornithology 6.1 (1990): 120-128. Web. 6 Aug. 2014.

6 “Window Collisions.” The Cornell Lab of Ornithology. Cornell Lab of Ornithology, 2007. Web. 8 Aug. 2014. <>.

7 Klem, Jr., Daniel, and Peter G. Saenger. “Evaluating the Effectiveness of Select Visual Signals to Prevent Bird-Window Collisions.” The Wilson Journal of Ornithology 125.2 (2013): 406-411. Web. 6 Aug. 2014.