Why Birds Fly Into Windows—and How to Prevent It From Happening

The National Audubon Society explains why birds fly into windows, and offers tips on how to safely stop them from hitting your home.

It's incredibly startling to hear that unfortunate thwack of a bird flying right into your window. While these beautiful creatures have exceptional navigation systems—many migrate long distances during seasonal changes—windows create a challenging obstacle for them.

Unfortunately, flying into a window isn't just unpleasant for the birds, the impact could cause significant injuries. In some cases, this head-on collision can prove fatal, particularly if the bird is on a migration path or trying to escape a predator, when birds tend to fly at faster speeds and become confused when they see what appears to be an empty space.

So why do these seemingly smart creatures fly into windows, and is there anything you can do to prevent the issue? We asked experts from the National Audubon Society to share their insights.

Related: How to Stop Woodpeckers from Destroying Your Home's Siding

Why Do Birds Fly Into Windows?

So, why is it so common for birds to fly into glass windows? "Birds fly into windows because they don't perceive them as hard barriers," explains John Rowden, senior director of bird-friendly communities at the National Audubon Society. "They may see mirror-like reflections in the glass that look like space or habitat that is appropriate to fly towards, or they don't see the glass at all if it's transparent and there's something on the other side they want to fly toward."

In other words, they may interpret the glass—which often creates a reflection of the outside—as a continuation of the sky.

4 Ways to Prevent Birds From Flying Into Windows

Make the Glass More Visible

The best way to protect wild birds from flying into your windows is to ensure that your windows are more visible.

"If people want to make glass visible to birds, there are a number of ways to do it—often with things they may already have around the house," says Rowden. "People can use decals, stickers, string, paint, tape—anything that birds can see and avoid—to create a pattern on the glass that will help the birds see it as a barrier and avoid it."

You can do this in several ways, including patterned window film, screens, or nets. When you aren't using the window. You can also place decorative decals over the windows to deter birds from the area.

Katie Weeks, director of community education at Audubon Southwest, says that a more subtle way to make glass more visible to birds is to create a grid of small dots with chalk markers. "This is a simple DIY solution to help birds detect glass without substantially obscuring human view," she says. "Birds are often thrown off by the reflection of plants and the sky and don’t recognize glass as a solid barrier. Adding details to help them detect those."

Turn Lights Off at Night and Close Curtains

Weeks strongly recommends turning off your lights and closing your curtains or blinds once the sun sets. "Artificial light can be particularly dangerous for migrating birds as they travel long distances," she says. "Lights can disorient birds and draw them off course, as well as create nighttime window strike hazards by illuminating indoor spaces."

An annual Lights Out project in New York City reduced hundreds of bird collisions by turning off the 9/11 memorial for just 20 to 30 minutes at a time, she adds.

Add Barriers in Front of Your Window

If possible, add elements in front of your windows that prevent a bird from even seeing the window in the first place, Rowden says. Trees and plants can help with this, as can awnings, and shutters. This might not be completely foolproof, but it can certainly reduce the number of instances a bird collides into your window.

Place Bird Feeders Close to Windows

This might sound counterintuitive, but placing bird feeders next to your window—even directly on the window—can help prevent birds from flying into the glass. "Research has shown that feeders closer than 3 feet prevent birds from building up enough momentum to harm themselves if startled," Weeks says. "Pairing this strategy with additional bird-friendly glass is one of the most effective ways to reduce window strikes."

What to Do if a Bird Flies Into Your Window

In the event a bird does fly into your window, there are a few things you can do to help improve its chances of survival.

"If you can find the bird, make sure it’s in a safe place, out of the way of foot traffic and other threats. Gently moving it under a bush or off the sidewalk is helpful, but even better would be leaving them alone," Weeks says. "Many times, they recover after 20 minutes or so and fly away, so you want to just reduce the stress and any further injury."

If the bird is notably injured, the best thing you can do is get them to a certified wildlife rehabilitator. Wild birds require very specific care, and are protected by both state and federal law. Although intentions are usually good, providing untrained care can often do more harm than good for wild birds.

"If they are not recovering after 20 minutes, you can gently place them in a small box with air holes, then transporting them to a rehabber," Weeks says. "Again, you want to be gentle and quiet to reduce any additional stress on their little bodies."

It’s a sad reality, but in many cases, the bird will often die due to internal injuries—even if it's able to fly away. Each year, approximately 1 billion birds die from window strikes in the U.S. One of the most important things you can do is to prevent injury altogether by following the advice above and building and creating more bird-friendly communities.