Bird Window Collision Prevention

As many as 1 billion birds are estimated to die from window collisions in the United States every year. Detroit Bird Alliance is working to change that. 

Glass is dangerous for birds because it reflects sky and trees which birds see as a continuation of their flightpath. Migrating birds may collide into windows during spring and fall migration periods. Birds also are at risk all year long, as they are lured toward windows by adjacent bird feeders, bird baths, fruit-bearing trees, and other attractions.  

Unfortunately, a bird hitting glass is very different from a human accidentally walking into a glass door. Birds travel at a much faster speed, and also have hollow bones far more susceptible to breaking and to fatal injuries.

How can I prevent bird-window collisions?

Half of all bird-window collisions happen at residential buildings. 

Make your home windows more visible to birds with:

  • Exterior window screens

  • Window coverings such as slatted blinds or shutters that break up the reflection  

  • Window art 

    • Chalk markers, oil-based pens, non-toxic tempera, or acrylic paint are all easy-to-use products and a fun way to make your windows visible to birds. 

    • Designs must be placed on the outside of the glass.

    • Graphics, lines, dots, etc., must follow the 2x4-inch spacing rule to prevent birds from trying to fly through the gaps. Some sources recommend even 2x2 inches to deter tiny birds like hummingbirds.

  • Window decals spaced no more than two inches apart

    • Feather Friendly Window Markers. Adhesive dots are applied with tape strips at two-inch intervals to the exterior surface of glass. You can see this product displayed on several buildings at the Detroit Zoo. 

    • Acopian BirdSavers. These hanging “Zen Curtains” are cost-effective and very easy to install. Besides saving birds, they are elegant and aesthetically pleasing. Order the product or learn how to make your own.

    • American Bird Conservancy (ABC) BirdTape. Simple and affordable, ABC BirdTape is easy to install and can be bought at most Wild Birds Unlimited stores. This translucent tape allows light through but is also highly effective at preventing bird strikes.

    • CollidEscape. Comes in perforated sheets that cover the outside while still allowing clear views from inside. These are a great option for businesses or public buildings because they can be printed with images for visitors to view from the outside.

Detroit Bird Alliance is happy to help you make your windows bird-safe. Contact us to find the perfect bird-safe window solution for you!

How is Detroit Bird Alliance Helping?

Detroit plays an important role in bird migration because the city is located at the intersection of two major North American migration paths. Millions of birds – including warblers, hummingbirds, and flycatchers with declining populations – migrate through Detroit every spring and fall.

Recognized by the U.S. Fish and Wildlife Service as an Urban Bird Treaty city, Detroit has a responsibility to provide safe passage to the birds that travel our flyway in the spring as they fly north to their breeding grounds and in the fall as they return to their winter homes.

Partnering to Prevent Bird-Window Collisions 

Detroit Bird Alliance is partnering with Wayne State University and Detroit Zoological Society to install bird-safe window retrofits along with signs and educational outreach around the Wayne State campus. 

For the past five years, Detroit Bird Alliance staff and volunteers have been surveying buildings around the Wayne State campus for bird-window collisions. We use this data, paired with feasibility and outreach value, to select locations for bird-safe window retrofits.  

The Wayne State campus has ample greenspace and several low-rise buildings with extensive and uninterrupted glass. Wayne State also offers a space where education, sustainability, and innovation are all encouraged, creating the perfect opportunity to address bird-building collisions.

Bird-friendly Building Design

Detroit Bird Alliance is raising awareness about the importance of bird-friendly building design to reduce the risk to birds. Every building poses a potential threat to birds. However, a thoughtful approach to design can incorporate bird-friendly elements and strategies that are cost-neutral. 

Bird-friendly building and landscape designs can significantly reduce the number of bird collisions. Bird-friendly design often goes hand-in-hand with energy efficiency which saves money. Learn more about bird-friendly building design.

Report a Window Collision

If you find a bird — injured or deceased — that appears to have hit a window or building, please take a picture and report the incident to Global Bird Collision Mapper.

You can easily register and report any collision incident and where the bird was found. This information is extremely helpful to better understand bird collisions and especially to Detroit Bird Alliance in order to determine which buildings are most dangerous for birds.

FAQs

  • There are four main reasons why birds collide with windows. Birds are usually attempting to:

    1) fly through the sky reflected in the glass

    2) fly toward vegetation such as trees or shrubs reflected in the glass

    3) fly toward house plants on the inside of the glass

    4) fly through glass corridors or walkways because they can see all the way through them

  • Both humans and birds have a hard time seeing glass. People accidentally walk into a glass door but can use context clues to identify there is glass. We see streaks, cracks, window panes, or the rest of the building and know, without thinking about it, that there is glass.

    Birds and most wildlife do not understand the concept of glass and cannot use visual cues to see glass. If a bird hits glass and survives, it may learn to be cautious of that specific area, but it will not apply that understanding to avoid all glass.

  • Many people are surprised by the number of birds killed from window collisions because they rarely see a dead bird below their windows. Studies have shown that many birds will not die instantly from a window collision, but instead suffer an injury that becomes fatal. Many collision victims face a broken bone or head trauma. In their weakened state, birds are unable to feed or become an easy meal for a predator such as a rat, cat, or raccoon.

    Even when a bird is killed on impact, we rarely see them because a scavenger or urban predator finds them first. Some predators have even learned to patrol windows and wait for these easy meals during dusk and dawn when birds are most active.

  • Detroit plays an important role in bird migration because the city is located at the intersection of two major North American migration paths, Millions of birds – including warblers, hummingbirds and flycatchers with declining populations – migrate through Detroit every spring and fall.

    Recognized by the U.S. Fish and Wildlife Service as an Urban Bird Treaty city, Detroit has a responsibility to provide safe passage to the birds that travel our flyway in the spring as they fly north to their breeding grounds and in the fall as they return to their winter homes.