Given the hundreds of millions of birds killed every year due to collisions with glass on human-built structures, bird window strikes are a major factor in the decline of bird populations globally. Additionally, the collisions subject these delicate animals to an untimely, cruel and gruesome death. This is caused by glass on all types of structures—from tall skyscrapers to home windows to railings. Glass collisions do not discriminate between species, sex, age, geography or seasons. It is a constant threat to all birds.
It is both the reflective and transparent characteristics of glass that make windows and facades dangerous for birds. They see reflections of vegetation and sky and respond to it as if the reflections are reality. Birds might also see a flight path through a window, a glazed building corner or glass walkway (the “passage effect”). There is no barrier perceived and they fly into the glass causing instant death or severe head trauma that they eventually die from, or because they are injured, fall prey to scavengers.
Glass as a design element has many purposes, including providing a feeling of openness, to bring natural light into a building, while also providing thermal protection from heat and cold. Advances in glass technology make it an ideal building and design material. This along with green building practices that focus on energy efficiency through the use of natural light add up to more and more glass being utilized in architecture, which translates to increasingly dangerous conditions for birds.
Over recent years, awareness of and education about the collisions issue has grown. The call for the implementation of bird-friendly design considerations has traction not only in the architectural and building community, but also in state and city governments. Avian advocacy efforts have given rise to many cities and states adopting voluntary, sometimes mandatory, bird-friendly design practices, including the use of bird-friendly glazing treatments and lighting elements. Additionally, U.S. Green Building Council’s LEED program has an innovation credit in its rating system, Pilot Credit 55: Bird Collision Deterrence. This has established an important incentive for architects and building owners to adopt bird-friendly design methods.
Because birds, unlike people, do not have the capability to read contextual architectural clues alerting to the presence of a clear piece of glass, something must be done to create a “visual signal” on the glass - patterns that birds can recognize.
There are many strategies to create these bird-friendly patterns for both existing and new glass, but it is important to keep in mind the “2 x 4 rule” which states that patterns should not be spaced more than 2 inches apart horizontally and 4 inches apart vertically to be effective at deterring collisions. Visit our Resources section for more information.
ARNOLD GLAS is committed to support, what we call the 3 Pillars of Bird-Friendly Architecture: Awareness and Education about the bird window collisions issue, making Bird-Friendly Glazing Solutions available, and Creating Behavioral Change in architectural design and building practices. These three things are essential elements in facilitating change, and representatives from each pillar must cooperate, for without one the others will not achieve their goal.
Solutions for existing windows:
Awareness & Education: The first step in solving this issue is one of awareness and education about the dangers of birds and glass. This is the work of advocacy groups like American Bird Conservancy, Audubon, and Ornithologists.
Behavior Change: And lastly, a behavior shift must occur. Architects, planners, building owners must opt for bird-friendly design. Supporting policy and legislation are also crucial for this change – for example U.S. Green Building Council’s LEED Pilot Credit 55: Bird Collision Deterrence and the formal adoption of Bird-Friendly Building Guidelines such as San Francisco’s Standards for Bird-Safe Buildings.
Solutions: The next step is that there have to be solutions to the problem; bird-friendly glass options. Solutions must be available, deliverable, affordable and able to meet other requirements of glass in buildings, such as energy efficiency and safety. This is the responsibility of manufacturers.
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