Window Collisions


Windows Can Be Deadly For Birds.

Ornithologists estimate that up to 100 million birds are killed each year by collisions with windows. These collisions usually involve small songbirds, such as finches, that may fall unnoticed to the ground. Sometimes the birds are merely stunned and recover in a few moments. Often, though, window hits lead to severe internal injuries and death.


Why Birds Collide With Windows.

It’s thought that birds hit windows because they see the landscape—trees, sky, clouds—reflected on the glass surface but do not realize that a hard, transparent surface lies between them and that apparent open space. Panicking birds, fleeing for cover to escape predators, are even more likely to fly into windows.


Window Collisions.

Window collisions are something you should be aware of and try to prevent, especially if you feed wild birds in your backyard. Start by identifying which window is the problem. You might not always see or hear birds striking your windows. Check the ground below your windows periodically. If you find dead birds, move your feeders or modify the windows. Birds face plenty of natural dangers. Let’s not subject them to unnatural ones.


Try some of these ideas to make your windows safer:

  • Relocate feeders and other attractants.openspace01
  • Avoid apparent visual tunnels.
  • Break up external reflections with a pattern of decals.
  • Disrupt reflections with spray-on materials or soap.
  • Attach objects to deter birds.
  • Reduce reflections with trees or install awnings.
  • Cover windows with netting.
  • Install windows tilting downwards.


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Help! How do I stop birds from hitting our windows?

FLAP “Make Your Home Safe For Birds”

American Bird Conservancy Bird Friendly Building Guide

Albuquerque Downtown Window Strike Survey Summary

Links to window collision deterrent websites

Three tips for using decals and paint on windows

  1. Use multiple decals; create a pattern that covers the window uniformly. Elements arranged in columns should be four inches apart. Elements placed in rows should be two inches apart. This is often called the 2 x 4 Rule.
  2. Elements should be at least one-eighth inch in width and should contrast as much as possible with the windowpane.
  3. Patterns can be placed on the inside or outside of a window that is transparent. If the window is reflective, the pattern must be applied to the outside.

Five bird deterrents that don’t work

  1. Hawk silhouettes: One window decal in the shape of a hawk will not frighten birds. Shape is not important.
  2. Single window decals: Affixing a single decal to a window will not deter birds. To lessen the area of exposed glass and help make a window visible to birds, use multiple decals (even multiple decals in the shape of a hawk).
  3. Plastic owls: Birds learn quickly that a motionless plastic owl is not a threat.
  4. Noise deterrents: Common noise deterrents — high-frequency ultrasound, noise cannons, and recorded distress calls — are ineffective at preventing birds from colliding with windows.
  5. Magnetic fields: Some deterrents emit a magnetic field said to disrupt birds’ geomagnetic orientation and encourage them to avoid the area. Magnetic fields are not effective at protecting birds from window collisions.

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