Can Birds See Glass Windows and Doors?

It was a bright, sunny day when I heard a loud thud against my living room window. I rushed over to see what had happened, only to find a small, stunned bird lying on the patio. It had flown straight into the glass, mistaking it for open space. This incident, while distressing, is not uncommon. In fact, it’s estimated that up to 1 billion birds die each year from collisions with glass on buildings in the United States alone.

Can Birds See Glass?

The short answer is no, birds cannot easily see glass. This is not a matter of species or time of day— it’s a fundamental aspect of how birds perceive their environment. To birds, glass appears invisible or reflective depending on lighting conditions and the angle of view. When it’s invisible, birds simply don’t realize there’s a barrier in their flight path. When it’s reflective, they see it as more open space or a continuation of the surrounding environment, which can be equally misleading.

Why Do Birds Hit Windows?

Birds hit windows primarily because they don’t perceive glass as a solid barrier. Brian Cunningham, Director of Outreach and Nature Education for Wild Birds Unlimited, Inc, explains it like this:

“Birds have trouble recognizing glass windows around our homes or buildings as a barrier until, like people, they learn it is not a passage. They can mistake the window’s reflection of the sky or yard for safe passage.”

They either don’t see it at all, or they see reflections of the sky, trees or other appealing habitats. This misperception is due to the fact that birds’ vision is primarily adapted for distance and motion detection, not for discerning reflections or transparent surfaces. Another contributing factor is the time of year.

“The research I know of about seasonality of window strikes suggests that spring and fall are the worst times of the year, because not only are there resident birds that can collide, but there are also migrants on the move at those times.,” says Emma Greig, Ph.D., from the Cornell Lab of Ornithology and Project FeederWatch.

How To Make Windows and Doors More Visible to Birds

Making windows and glass doors more visible to birds can significantly reduce the number of fatal bird strikes. This protects your feathered friends and prevents potential damage to your property.

Here are some strategies:

Use window decals

Window decals are an easy and cost-effective solution. These stickers adhere to the glass and create a visual barrier that birds can see. They come in various shapes and sizes, from bird silhouettes to more decorative designs.

The key to using decals effectively is to place them close enough together so that birds don’t perceive the space between them as a possible route. A good rule of thumb is to place them no more than two to four inches apart if you’re trying to deter small birds, and no more than four to six inches apart for larger birds.

Install bird-safe glass

Bird-safe glass is designed with a pattern that is visible to birds but barely noticeable to humans. This pattern is created by applying a special coating to the glass that reflects ultraviolet light, which birds can see but humans cannot.

While bird-safe glass can be a more expensive option, it’s highly effective and doesn’t alter the appearance of your windows significantly from a human perspective. It’s an excellent choice if you’re building a new home or planning to replace your windows.

Apply window films or screens

Window films or screens can be applied to the exterior of windows, creating a visual and physical barrier that birds can detect. They also have the added benefit of reducing heat and glare inside your home, which can help lower your energy costs.

Window films, such as window tinting or low-e films, are typically transparent and have patterns that are visible to birds. Screens, on the other hand, add a layer of texture to the window that birds can easily see and avoid. Both options are relatively easy to install and can be removed without damaging the window.

Hang objects outside the window

Hanging objects such as wind chimes, sun catchers or even strips of brightly colored tape can deter birds. The movement and reflections these objects create can signal to birds that there’s a solid barrier ahead.

This method can be particularly effective if you have a problem with birds hitting a specific window. The objects not only break up the reflection on the glass but also add a bit of decorative flair to your home.