Glass Collisions

LEED Pilot Credit

Vassar Bridge Science Building, N.Y. ©Christine Sheppard
The U.S. Green Building Council on Bird-friendly Design: LEED Pilot Credit #55

The U.S. Green Building Council (USGBC) was established as a nonprofit organization in 1993 to promote sustainable design. At that time, the newly founded group created the Leadership in Energy and Environmental Design or LEED program, partnering with a wide coalition of environmental groups, government agencies, industry stakeholders, and others.

The LEED rating system awards levels of certification based on a project's accumulation of points for using sustainable options for systems, including energy, water, materials, and siting. Initially, the primary focus for sustainability was on energy and water issues, but over time, LEED has evolved through multiple versions (currently LEED v4.1) to include the impact of construction on wildlife, along with other issues related to site selection. After ABC got involved, the program began to address the impacts of structures on birds after construction is completed.

USGBC recognized early that there might be sustainable strategies that did not fit easily into the credit structure, and allowed projects to submit for “innovation points.” A simple example was the awarding of points for providing bike racks and other amenities that promote sustainable transportation. Because many projects developed the same points independently, the LEED system developed a Pilot Credit Library to eliminate duplicated effort.


Why Birds Hit Glass

Birds, unlike humans, are unable to understand or learn the concept of ‘glass' as an invisible barrier that can also be a mirror. Birds take what they see literally – and glass can appear to be habitat they can fly into, whether the habitat is reflected, or seen through a pane of glass.

Photo of hummingbird


One of the initial goalsof ABC's Glass Collisions Programwas to add a credit to the LEED system, to be earned by adopting design strategies that would reduce bird mortality from collisions with glass. Early proposals used common recommendations, such as “increase visual noise on the façade.” However, LEED is strongly tied to quantification and metrics, and that type of recommendation did not work for the system. In 2009, ABC developed a glass rating program and it became possible to use the Threat Factors assigned to materials as the basis for a credit.

ABC's Dr. Christine Sheppard led a small team of architects that developed Pilot Credit #55: Bird Collision Deterrence, which was added to LEED in 2011 and was revised in 2015. The credit is now available for projects using any version of LEED.

The credit was modeled on traditional methods of calculating insulation ratings. Every material, glass and non-glass, on a building envelope is assigned a Threat Factor rating. These ratings are entered into a calculator along with the area covered by each material. Recognizing that the lower floors of any building are the most likely to pose a glass collision danger to birds, materials on the lower four floors are assigned a weighted threat factor — they count twice as much as materials used higher up on the same building.

One goal of the credit design was to provide flexibility to designers by allowing a wide range of materials and styles. USGBC reports that Pilot 55 is the most-used credit in the Pilot Credit Library. Examples of buildings that have earned the credit can be found in our Gallery.


From Bird Killer to Model Building

New York City's Jacob K. Javits Convention Center was a notorious source of bird collisions. When bird-friendly glass was installed as part of a major renovation to improve energy efficiency, collisions declined by more than 90 percent. Watch the video for a brief overview of the project.   


How to Keep Birds from Hitting Your Windows

Are birds colliding with your home or building? Use our guide to find solutions and protect birds!


Take Action for Birds

ABC is working hard to make federal buildings bird friendly. Join us today and ask Congress to pass the Bird-Safe Buildings Act!


Visit our photo gallery to see how a variety of materials and techniques can be used to make buildings safe for birds and great for people.

News, Updates, and More

Bird Collisions on ABC's Blog

Check out BirdCalls Blog for frequent updates and insights into birds and window collisions…. Read more >>