Birds often mistake glass windows for open sky or reflections of trees, leading to potentially fatal collisions. Up to a billion birds die annually in the U.S. alone from window strikes. Fortunately, there are numerous effective methods to prevent these tragic accidents and make your windows bird-safe.
american goldfinch killed by window strike
Understanding Why Birds Hit Windows
Birds collide with windows for two primary reasons: daytime reflections and nighttime attraction to lights. During the day, windows reflect the sky or surrounding vegetation, creating an illusion of a safe passage. At night, especially during migration, artificial lights disorient birds, drawing them toward buildings and increasing the risk of collisions.
imprint of dove on plate glass window
Identifying High-Risk Windows
Before implementing solutions, identify windows most likely to cause bird strikes. Large picture windows, windows at right angles to each other, and windows reflecting trees or sky are particularly hazardous. Observe your windows from a bird’s perspective to pinpoint problem areas. Windows near bird feeders, regardless of distance, should also be addressed.
Effective Bird Deterrents for Windows
Several methods can be employed to deter birds from flying into windows. The key is to break up reflections and make the glass visible to birds.
Applying Treatments to Existing Windows
- Visual Markers: Apply visual markers to the outside surface of the window. Effective options include:
- Tempera Paint or Soap: Create a grid pattern with spaces no larger than 2 inches apart.
- Decals and Stickers: Use commercially available decals or create your own with tape or other materials. Ensure decals are spaced no more than 2 inches apart. Hawk silhouettes are ineffective.
- Dot Patterns and Tape: Specialized tapes with pre-spaced dot patterns offer a convenient solution.
- Acopian BirdSavers (Zen Curtains): These closely spaced cords hang vertically over windows, breaking up reflections effectively.
reflection of foliage in window – hazard to birds
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Screens and Netting:
- Screens: Install tight-fitting screens on the outside of windows.
- Netting: Hang netting at least 3 inches away from the window surface, creating a buffer zone.
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One-Way Transparent Film: These films allow visibility from the inside while making the window appear opaque from the outside.
Incorporating Bird-Safe Practices in New Construction
- External Shutters or Awnings: These can be closed to eliminate reflections.
- Exterior Screens: Design windows with screens installed on the outside.
- Vertical Blinds: Keep blinds partially closed to reduce reflectivity.
- Strategic Window Placement: Minimize windows reflecting sky or vegetation.
Reducing Nighttime Collisions: Lights Out
Reduce or eliminate outdoor lighting, especially during migration seasons. Switch to downward-facing fixtures to minimize light pollution and disorientation for birds.
Helping a Bird Injured by a Window Strike
If a bird strikes a window, gently capture it and place it in a dark, quiet container lined with soft material. Do not attempt to feed or water the bird. Contact a licensed wildlife rehabilitator immediately for further instructions.
By implementing these strategies, you can significantly reduce the risk of bird window strikes and contribute to avian conservation efforts.
