Designing With Bird Safety in Mind

Estimates have revealed that between 365 and 988 million birds die every year due to building collisions, but recent studies have presented an even more harrowing statistic. A 2024 study published by PLOS One revealed that approximately 60% of birds brought to wildlife rehabilitation centers after building collisions die during care, suggesting that overall collision mortality estimates exceed one billion birds in the U.S. annually.

Glass is one of the major offenders when it comes to bird-related deaths. Modern architecture has adopted this as a primary structural material for building envelopes, yet transparent and reflective glass are both highly detrimental to birds. To the avian eye, transparent glass does not appear to be a solid barrier, leading them to see the space behind the clear glass as an open area, which can cause severe collisions. Reflective glass, often seen on high-rises and skyscrapers, reflects the sky or other surrounding environmental elements such as trees. Through birds’ vision, the building becomes the object it reflects, which can be disorienting and fatal.

“Each species has a unique umwelt,” said Peter Duckworth-Pilkington, a sustainable design leader in our Toronto architecture studio, “so it can be difficult for us to anticipate how another species may react to a novel stimulus, and therefore, it is critical to rely on scientific studies and observations.” 

While buildings are designed with human users in mind, other species will inevitably encounter these structures and interact with them differently, prompting the need for buildings to be designed for all species. A growing list of cities has instituted bird-safe measures in their design and construction practices, but birds continue to fall victim to buildings regularly, further encouraging the need to reevaluate how we approach the spaces we use daily. 

Understanding Bird-Safe Design

Bird-safe design entails implementing a careful approach that considers surrounding wildlife during the design process. “Our built environment shouldn’t harm any of the surrounding ecosystems, especially birds,” said Annette Veliz, an architect from our New York City architecture studio. “When it comes to species that fly and migrate through cities, buildings can become major obstacles. It all starts with designing buildings that are not deceiving to birds.”

This means diligently considering elements that attract birds, such as large swathes of transparent glass, plants in windows, distracting lighting and large louvers that could trap them. Migration patterns are also important to consider in the planning and design processes. If a tall building is in a specific migration path, developers and designers need to be conscientious of the materials they use and meticulous about their light usage during certain times of the year when some species are migrating.

Glass With a Purpose

While common building features such as transparent glass and bright interior or exterior lighting can go virtually unnoticed by people, what seems intuitive to humans can be disorienting and dangerous to other animals. To avoid these collisions, architects and designers can consider various window treatments and features, such as:

• Patterned glass
• Fritted glass, which can also block out sun rays and help cut down on cooling costs
• Translucent or frosted glass
• UV-coated glass, which is visible to most birds but not humans
• An additional exterior layer, such as a screen or netting

Instead of regarding these features as distractions from a building’s aesthetics, architects and designers can view these treatments as ways to advance the function of their design. For example, at the Minwamon Building, one of a suite of three new builds at the Chalk River Campus for Canadian Nuclear Laboratories (CNL), the design team used frosted and fritted glass gradient, which not only provides a visual barrier for birds but also controls solar gain, reducing the need for cooling operations. “That was highly critical for the CNL buildings,” Duckworth-Pilkington said. “Considering they’re in a very remote and naturalized location, we wanted to have as little impact as possible on generally untouched land.” 

Protective Layers

In addition to frit patterns or gradients, other façade details and building screens can also deter bird collisions. At CNL’s Minwamon Building, the design team employed a wood slat system and exterior shading terracotta system that covers the reflective glass and minimizes bird impact.

Two additional HDR-designed projects, the Mayo Clinic Anna-Maria and Stephen Kellen Building in Minnesota and the Almoosa Rehabilitation Hospital in Saudi Arabia, further exemplify how façade design can hold multiple functions. While designed primarily for energy reduction, privacy and mitigating solar heat gain, these designs can also help deter birds from colliding with the building.

Light Pollution and Solutions

Similar to a deceiving exterior, artificial lighting and skyglow can be highly disorienting to birds, especially migratory birds that fly at night and aren’t accustomed to the environments they’re flying through. 

“Light pollution is complicated,” Veliz said. “As birds follow wind patterns and their internal GPS to safely migrate, light pollution can disrupt this and interfere with their navigation.” These complications can cause them to miss their destination or divert them from other paths, ultimately altering their routes and placing them in an unfamiliar and potentially deadly environment. 

In major cities where light pollution is a common attribute, the simple act of turning off lights at night can create a world of difference for migratory birds. After ornithologist David Willard found hundreds of dead birds around McCormick Place Lakeside Center in Chicago, he conducted studies highlighting the importance of lighting in preventing bird collisions. When building management began turning off lights in half of the building, researchers found that this dramatically reduced bird strikes by six times in the fall and by eleven times in the spring.

While turning off lights more frequently or creating light sensors are simple solutions, security concerns have been a common opponent to limited lighting at night. Residents often opt to keep the lights on as a security measure, but excessive bright light for security purposes can contribute to collisions and, in some cases, even illuminate nesting areas, disturbing birds and highlighting targets for predators. 

To combat this issue, project teams have had to become creative with their lighting plans. For example, the team at The Ottawa Hospital sought to create a safe and secure space that offered opportunities for respite while keeping wildlife safety in mind. To maintain this balance of serenity and security for building users, the team covered each strategically located light pole with a shield so only paths were illuminated, and natural areas were left dark. This provided ample security lighting while sustaining a calm, natural environment for humans and the surrounding wildlife.

Feeding Two Birds with One Hand

Sustainable building initiatives and bird-friendly measures are important aspects of rethinking a building’s impact on the surrounding ecosystem and the potential for a regenerative future. By implementing regenerative design strategies — a concept that focuses on renewal-focused solutions where the built environment contributes to positive gains rather than merely doing less harm — buildings can be designed to reconnect humans and nature. 

A clear example of a design strategy that can help a building give back can be seen through the addition of properly maintained green roofs. “For it to be a successful green roof, it can’t just be a space for people to have lunch,” Veliz said. “It should have the right plants and trees and be open to all species, including birds.” Green roofs, which can absorb water in extreme weather events and help maintain cooler air in buildings, are not just places of respite for building residents; they also serve as a haven for local wildlife in urban settings and form a tangible connection between nature and the built environment.

Embracing Nature with Resiliency

“Humans can’t live outside of nature — the planet is always reminding us of this,” Duckworth-Pilkington said. “As we move away from single issues, such as only focusing on employing bird-friendly design, we can see through a more holistic lens and recognize the advantage of creating structures that encourage biodiversity, reduce our impact and provide healthy environments for all living species.”

Recognizing the importance of bird-friendly design is integral to creating safer spaces for the avian population. The ultimate goal, however, requires a shift in focus from the built environment simply doing less harm to actively contributing through resilient structures that protect the future for all. 

Annette Veliz is an architect in our New York City studio. An avid supporter of birds and wildlife, Annette is a part of Project Safe Flight, a volunteer-based program of NYC Bird Alliance that helps pinpoint unsafe buildings, advocates for bird-friendly design practices and contributes to research on the dangerous impact of light pollution on migratory birds.

Peter Duckworth-Pilkington is a sustainable design leader in our Toronto studio. Peter’s 25 years of experience include work on a wide range of sustainable architecture projects and initiatives, such as LEED schools, libraries, sports venues and high-rise mixed-use developments across Canada.