Last month, the death of Flaco the Owl, a New York City resident, made headlines worldwide. A longtime attraction at the city’s Central Park Zoo, the Eurasian eagle owl had escaped into the wild in 2023 after his enclosure was vandalized. During his year of freedom, Flaco had been spotted in several locations throughout the city, but in late February he crashed into a midrise building on the Upper West Side and died on impact.
Bird collisions have risen dramatically as the urban environment has grown. Buildings with extensive glass exteriors, such as high-rise glass towers, low-rise commercial properties, and even single-family homes, pose a particular threat to bird populations. While most avian species have excellent vision, glass is essentially invisible to birds: It can appear clear or reflective, mirroring the sky or surrounding foliage. Some researchers estimate that, in North America alone, more than a billion birds die each year after striking buildings. A recent event in Chicago resulted in 1,000 birds colliding into a single building during migration.
What can architects do to reduce bird collisions and improve wildlife preservation? Bird-safe glazing is one promising solution. It can mitigate bird collisions, promote biodiversity, and create sustainable urban environments.
Bird-Safe Glazing
Bird-safe glazing is designed with marker patterns and visual cues that deter birds from colliding with glass. Fritted glass, etched patterns, adhesive films, and UV-reflective glass are among the solutions being implemented. In new construction, these conservation features can be integrated into the design with fairly simple guidelines and a slight premium in glazing cost. Retrofitting existing structures to make them more bird-friendly can be challenging but it is not impossible.
Bird-Friendly Design Principles
Bird-safe buildings involve more than just glass, however. Building orientation and placement play crucial roles in minimizing bird collisions. Thoughtful landscape design that incorporates vegetation, water features, and feeders can attract birds away from hazardous areas.
Lighting design also matters, as migratory birds that fly at night can often be drawn off course by bright lights in tall glass buildings. Utilizing dark-sky compliant exterior fixtures can drastically reduce this environmental impact while lowering energy loads.
Several recent HGA projects have successfully implemented bird-safe glazing. For the Marquette College of Nursing in Milwaukee, we utilized UV-reflective dots on the outer surface to make glazing more visible to birds without obstructing views from the interior. At a medical center in Pittsburgh, Pennsylvania, vertical lines were silkscreened at 4-inch intervals on the outer surface of the glazing to heighten visibility. Both projects referenced best practices like Audubon’s bird-safe fact-sheet and various state-led policies.
Collaborative Efforts and Policies
Addressing the issue of bird collisions requires collaboration among architects, conservationists, and researchers. Policymakers can also play a vital role in promoting bird-safe building design. Many building certifications, such as LEED, WELL Building Certification, and the Living Building Challenge, now offer credits and resources to address bird-safe glazing. Cities and states that have recently passed bird-safe building measures include:
- New York City
In 2019, New York introduced voluntary guidelines for bird-friendly building design. Bird-safe glazing and visual markers on glass facades are recommended. - San Francisco
In 2011, San Francisco became the first U. S. city to require bird-safe measures in new construction and major renovations of certain buildings. - Chicago
In 2020, Chicago mandated that bird-safe materials be used in the construction of new buildings and renovations of existing buildings. - Madison & Middleton, WI
City zoning ordinance requirements related to building design are intended to reduce bird collisions. - Minnesota
The Minnesota B3 Sustainable Building Guidelines include requirements for bird-safe design practices. When glazing is in scope, bird-friendly glazing and other strategies must be applied to minimize bird collisions. - California
The state’s Building Standards Code, also known as Title 24, includes requirements for bird-safe glazing in certain circumstances. It outlines standards for new construction and alterations to existing buildings to address bird collision risks. - Washington, D.C.
The district’s Wildlife Action Plan encourages the use of bird-friendly materials, including glazing treatments, to mitigate the risk of bird collisions.
The Future of Bird-Safe Glazing
Bird-safe glazing can help preserve avian species, and architects, developers, and building owners who choose bird-safe glazing have the power to reduce bird strikes and boost conservation. Such measures are yet one more way we can create sustainable cities—places that are ultimately friendly, safe, and healthy for birds and humans alike.
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