Bird-friendly glazing
Help prevent birds from colliding with windows and façades
Up to one billion bird deaths in the United States are attributed to collisions with buildings and other structures each year1. This document provides information on the problem, its relation to building glass and glazing, and offers potential solutions for architects, contractors, and fabricators. As the architectural community and glass industry work to address this issue, it is critical for audiences to understand collision causes, product testing, bird behavior, and solution options.
1The Condor: Ornithological Applications, 2014
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What are the benefits of bird-friendly glass?
Collision deterrence
Adding visual contrast to the glass through various methods creates a visible marker to birds, helping them detect the glass as a physical barrier and avoid it. The effectiveness of the solution depends on the technology used as well as the size and spacing of the pattern elements. The building’s surroundings, lighting conditions and the outside reflectivity of the glazing also play a role in the solution’s effectiveness.
Aesthetics
Depending on the technology, bird-friendly glass solutions can be more or less visible to humans from the outside of the building. Bird-friendly glass treatments can be used as design elements to make a statement, or they may be more subtle for a minimalist look. From inside the building, the visibility of a bird deterrent depends on lighting and the complexity of scenery outside. Many patterns are designed to virtually disappear when viewed from a distance.
Energy performance
Bird-friendly solutions can be combined with high-performance coatings to provide thermal insulation and solar control properties to the glazing. These coatings can help maintain a comfortable temperature inside the building by reducing the amount of solar energy that enters through the glazing in the summer, or of heat escaping it during the winter.
Environmental stewardship
Birds play a critical role in ecosystems and economies around the world. Between providing food, controlling pests, enriching soil and other contributions, their impact on quality of life is immense. With many bird populations in decline, it becomes even more serious to address the problem of bird-window collisions. Bird-friendly glass can also contribute to LEED® Innovation Credit (“Bird Collision Deterrence,” BD+C: New Construction. v4.1).*
*Scott R. Loss, Sara S. Loss, Peter P. Marra and Tom Will, Bird–building Collisions in the United States: Estimates of Annual Mortality and Species Vulnerability, The Condor: Ornithological Applications in January 2014.
Why do birds collide with glass?
Bird-window collisions can happen anywhere birds and buildings are present. In fact, low-slung buildings in the suburbs account for a much higher percentage of total bird-window collisions.
Most often, birds collide with glass buildings and windows because they don’t perceive glass as a barrier. This is a result of reflective and transparent qualities of glass, as well as building design and lighting.
Reflection
Birds cannot differentiate between actual and reflections of tree, sky, or habitat. Even lower reflecting glass can act like a mirror when it is bright outside and dark inside. When coupled with certain façade designs, the reflections can create areas that are visually confusing to birds. Reflective materials that provide adequate image formation, pose a danger to birds.
Transmission
When there is a direct line of sight from one window to another (e.g. walkways, corners, bus stops, or transparent wind/sound barriers), birds do not perceive the glass as a barrier, and may attempt to fly through, causing a collision. Also, birds can see wooded atriums or indoor plants as an inviting habitat.
Design
The design of the building and its location can have a significant impact on the collision risk as well as the maximum effectiveness of deterrents. Building shape, location, and landscaping (especially the anticipated height of the tree canopy once mature) all have considerable impact on the collision risk profile of the facility.
Lighting
Birds use the night sky and ambient light levels to aid their migration navigation. This causes nighttime collisions as lighting inside buildings, especially those buildings with potential habitat, attracts birds. Artificial lights, particularly those that point upward, can lure and trap birds in their haze, where they potentially fly to the point of exhaustion.
What Guardian Glass solutions help counteract collisions?
Evaluated by the American Bird Conservancy (ABC), Guardian bird-friendly solutions can pair with your favorite SunGuard™ low-E coatings to help meet the energy performance requirements, meet bird friendly building requirements and even support LEED® v5.0 Biodiverse Habitats Credits. Deciding which solution to use can depend on project criteria for cost, aesthetics, energy performance and efficacy.
- Bird1st™ UV - This solution has a subtle matte appearance that can blend into a façade. It is applied on surface 1 with a low-E coating on surface 2 for optimum performance from both materials. Can be paired with a wide range of SunGuard low-E coatings.
- Bird1st™ Etch - This solution typically has the least impact on human visibility and aesthetics. It is approved by the American Bird Conservancy while preserving clarity and views with advanced UV reflecting and absorbing technology. Can be paired with select SunGuard low-E coatings.
Guardian SunGuard
Paired with select Guardian SunGuard low-E coatings, Guardian Bird1st glass delivers on helping to create structures mindful of aesthetic and performance standards.
How do these solutions work?
Guardian Glass bird-friendly solutions visually signal an impending barrier to birds, helping decrease collisions as confirmed by acceptable Threat Factor scores from the American Bird Conservancy (ABC). Threat Factor indicates the percent of times in which birds will not avoid collision. ABC defines “bird-friendly” materials as having a Threat Factor ≤30.
Guardian bird-friendly solutions feature patterns strategically spaced at least 2" x 4" or 2" x 2" apart. The ABC champions the 2" x 2" Rule for the spacing of visual elements in order to effectively deter even small birds from collision, noting that 2" x 4" spacing of such elements can also significantly reduce collision for most species.
Test your knowledge about bird friendly glass solutions
Do you understand birds’ physiology and behavior, which are key elements in the development of our bird-friendly glass solutions? If not, we suggest you learn more about this topic thanks to our 10-question quiz!
