An estimated 365 million to one billion birds die from colliding with windows annually in the United States, the second leading cause of bird deaths in North America. Nearly half of these collisions occur at residential windows, with the rest occurring in cities with larger buildings covered in glass and bright lights.
Why do birds fly into glass?
Simply put, birds do not see glass. The bird sees a destination in the reflection of trees, shrubs, or sky in the glass. They may seek refuge in atriums or in buildings with plants placed near windows inside. Sometimes two windows directly across from each other create a corridor that a bird will try to fly through.
What you can do at home
Cover your windows.
There are a variety of inexpensive products that can be applied to the outside surface of windows. American Bird Conservancy has tested many products, including ABC Bird Tape, 3M Feather Friendly Design, and Acopian Bird Savers (Zen curtains). See helpful resources list below.
If you purchase decals online, remember to follow the 2” x 4” rule, or even better, the 2” x 2” rule, and place them on the outside surface of the glass. This means that the decals must be spaced 2” apart horizontally (in rows) and 4” apart vertically (lines running up and down). This is the minimum space a bird can fly through, and if the decals are too far apart, you will continue to have birds colliding with the window. It’s important to place stickers or decals on the outside surface of glass because this will break up any reflections that may attract birds and will also improve general visibility to birds.
UV stickers and decals are often ineffective because of poor spacing and will lose their UV in a short period of time. Hawk silhouettes are also ineffective due to poor spacing, and they do not “scare” birds away from glass.
Move your bird-feeders.
Place your bird-feeders within three feet of your windows. This diminishes the momentum gained by birds taking flight and reduces the likelihood of fatal impacts. We also recommend placing bird-feeders near bushes or something similar so birds can seek shelter from predators.
Turn lights off.
Since many birds migrate at night, turning lights off from 12–6 a.m. is especially important during migration seasons. If lights must be on, make sure they are shielded downward so that birds don’t get trapped in the upward beam of light. You can also put them on timers or motion sensors.
What to do if you find a stunned bird
It is important to get a stunned bird to a federally licensed avian wildlife rehabilitator as soon as possible. These birds may seem to wake up after a short period of time, but they can succumb to head trauma or internal bleeding from the collision even after 24 hours.
Gently pick the bird up and place it in a cardboard box lined with a paper towel or soft cloth.
Keep the box in a quiet, warm, and dark place until you are able to transport it to a rehabilitation facility.
Do not offer the bird food or water, as you may end up harming the bird further by aspirating it (getting food or water into the air way). Do not hold the bird in your hand. This can cause even more stress and harm to the bird and can diminish its chances of recovery.
You can view and download the handout from our online course “Audubon at Home: Protecting Birds from Window Collisions” with Jessie Griswold here.
Special thanks to our Conservation Committee member Jessie Griswold for providing this information. Data collected through window collision monitoring in Birmingham, Alabama, during migratory seasons in 2018 and 2019.