Design and Construction, Energy Management and Lighting, Maintenance and Operations, Safety

How to Prevent Bird Window Collisions

In early October, a major bird-collision event occurred in Chicago. While there were other collisions across the city, one building, McCormick Place, killed nearly 1,000 migrating birds in a single night. Although weather patterns played a role, McCormick’s reflective glass walls and bright lighting are known to be the problem.

Photo by Lynne Mecum, American Bird Conservancy

Collisions with glass result in a staggering loss of up to 1 billion birds each year in the United States. During peak migration every spring and fall, large numbers of injured and dead birds end up littering city sidewalks and properties across North America. Fortunately, preventing wild birds from crashing into windows is possible and can be a simple and inexpensive problem to solve.

American Bird Conservancy (ABC), a leading authority on preventing bird collisions, recommends the following bird-friendly solutions for facilities managers.

Products that Prevent Collisions

Birds cannot see or recognize transparent glass. When birds see plants or the sky reflected in windows, they do not know that there is a barrier they cannot fly through.

If you think you have a window collision problem at your building, you probably do as only a fraction of birds that hit windows die on the spot. Monitor the building by walking the perimeter and record the birds you find. This will reveal which areas need to be treated immediately.

For existing buildings, the easiest fix is to add commercially available bird-safe window treatments. New buildings can be designed using bird-friendly building strategies, including glass with minimal patterns on it. The majority of bird-friendly glass types have subtle patterns but are still transparent and provide a good view. Not any pattern will do as there are rules that define the types of patterns that birds are able to see.

Design elements do not have to be added directly to window panes to prevent bird collisions. Many buildings use shutters, grilles, or screens, including insect and solar screens, to reduce the amount of visible or reflective glass. Patterned window films and paracord products that cover less than 10% of the glass surface are also options.

Another method of reducing bird collisions is to choose glass other than typical clear panes. Frosted, glass-block, and stained-glass windows can be visible to birds.

Hundreds of solutions exist, ranging from simple glass and screen treatments to one-of-a-kind design approaches. Our product database includes a long list of building materials that are tested and rated by ABC scientists.

Decrease Light Pollution

Most birds migrate at night, using the stars to navigate for thousands of miles in a short period of days. Artificial light at night disorients migrating birds, luring them toward and into urban centers. Once birds land near buildings, they are at increased risk of glass collisions. The dangers posed to birds by artificial light grow each year as expanding development illuminates more of the night sky.

Individual buildings are encouraged to turn off all non-necessary interior and exterior lights from midnight until after sunrise during spring (April 1 – June 1) and fall (August 15 – November 1) migration. For new fixtures, we recommend using lighting certified by the Dark Sky Association.

By taking actions to counteract light pollution, facilities managers and property owners can help decrease the amount of bird deaths year-round, especially in spring and fall during peak migration. Reducing lighting also saves money and reduces CO2 emissions. ABC recommends that more places follow the lead of New York City and encourages bird-friendly policy solutions.

LEED-Rated Buildings

Most LEED-rated buildings are not considered bird-friendly. However, the LEED certification system does have an optional credit, Bird Collision Deterrence, to allow architects and developers to get LEED credit for designing with birds in mind.

Regardless of LEED rating, ABC strongly encourages decision-makers and facilities managers to incorporate bird-friendly buildings guidelines into their designs. Examples of bird-friendly buildings can be found in ABC’s Gallery.

Legislation, Ordinances, and Code

One of the most effective actions is passage of ordinances requiring that new construction include bird-friendly strategies. In the U.S., many municipalities have already adopted bird-friendly standards. For simple instructions, including a model ordinance, check out ABC’s Legislative Toolkit.

Facilities management is uniquely positioned to drive and integrate sustainable practices. Solving a problem of this size requires big thinking, bold ideas, and collective action. Together we can build buildings that are no longer a leading threat to birds.

Bryan Lenz is the Bird City Network Director and Glass Collisions Program Director at American Bird Conservancy, a nonprofit dedicated to conserving wild birds and their habitats throughout the Americas.

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