Reducing Collisions Can Save Energy and Migratory Birds

David Sibley, noted author of a bird watching guides, has written an opinion editorial on the need to incorporate bird-friendly features into building and landscape design and operation.

“Green Buildings” Should Save Energy and Migratory Birds
By David Sibley

It becomes clearer every day that relatively small changes to building designs can be good for the environment and for the bottom line. The Greenbuild International Conference and Expo recently brought the revolution of “green buildings” to Chicago. The gathering of 18,000 industry experts hosted by the U.S. Green Building Council is another indication of the growing environmental movement within the architectural and construction constituencies. One thing that is largely missing from the green building debate, however, is the impact that buildings can have on migratory birds.


Most home owners have experienced the shock of a bird colliding with their living room window at one point or another. In fact, it is estimated that as many as 900 million birds are killed each year when they collide with glass windows on homes, offices, and other buildings across the country. Many of these birds are killed immediately in collisions with the building structures. Others fall to the ground where they subsequently succumb to their injuries, or are too weak or dazed to escape gulls, cats, and other predators. The cumulative toll of these collisions on birds is significant, and when combined with habitat loss, pesticides, climate change, and a host of other human-induced threats, they can exacerbate population declines already being experienced by many migratory songbirds.

There are three critical problems at play in bird/building collisions that can be addressed by architects and building managers. Firstly, birds often see vegetation or sky reflected in windows, and simply try to fly through the glass. In other cases, birds can see right through a building and try to fly through one window into the habitat they can see on the other side. Thirdly, while migrating at night, birds can become confused by the nighttime illuminations on buildings, and can crash into the structures, or get caught in “death spirals”, unable to escape the pull of the lights.


This bird mortality has not escaped the notice of birders, and local “Lights Out” campaigns are starting to catch on in cities such as New York, Chicago, and Toronto, where large, illuminated buildings attract migrating birds that are especially concentrated along shorelines. Many thousands of birds have already been saved as a result. A study in 2000 and 2001 by ornithologist Mary Hennen and other researchers from the Field Museum of Chicago found that turning off lights during migration season reduced bird deaths by 83%.Building owners and managers also save money, and contribute to energy conservation at the same time. It’s a win-win-win for the environment.

Design can make a huge difference too. For example, as reported in The New York Times on September 22, the Postal Service’s Morgan Processing and Distribution Center recently retrofitted 440 decorative, reflective glass panels with black vinyl to prevent the reflection of trees in Chelsea Park. The vinyl appears to have virtually eliminated bird collisions there. The New York Times’ own headquarters building is also a model for bird safe construction, using ceramic tubing to reduce the reflective properties of the building exterior.
Ultimately, the development of affordable glass that has a less reflective exterior surface could be the best long-term solution to the problem. Already, bird conservation organizations, as well as architects, planners, scientists, and glass engineers are working under the banner of the Bird-Safe Glass Working Group to promote the use of bird-safe glass products already available on the market, and to develop even more effective products in the future.


American Bird Conservancy is taking a national approach to preventing collisions, and aims to encourage “green building” designers to incorporate bird-safe designs. New York City Audubon has published a booklet, Bird-Safe Building Guidelines (, addressing new building construction as well as the retrofitting of old buildings to be bird safe. Other groups, such as the Bird Conservation Network ( and Fatal Light Awareness Program (, are at work on efforts in Chicago and Toronto.


Ultimately, everyone from homeowners and office workers, to builders, architects, and city and building managers, has a stake and can make a difference in this issue. To my mind though, the only truly green building is one that is designed to reduce energy consumption and protect neighboring wildlife such as migratory birds.

—David Sibley is the author of the Sibley Guide to Birds and Sibley’s Birding Basics.

American Bird Conservancy Launches Bird Collisions Campaign


American Bird Conservancy (ABC) announced today the start of its new Bird Collisions Campaign. Expanding on earlier successes in preventing bird collisions with communication towers, ABC is adding a full time staff member to its roster to focus on collisions issues, particularly building strikes. Every year, millions of birds are killed in collisions with windows on commercial and large city buildings, and homes across the nation. Some of the solutions, such as turning off lights in offices at night and reducing flood lighting on public buildings, are well understood but need broader implementation. Other solutions, such as bird-safe glass, are still being developed but have the potential to make significant differences. ABC will work with scientists, regulators, city officials, corporations, and architects and planners to further the development of these and other creative solutions that will help to reduce dramatically the toll resulting from these interactions. ABC’s Bird Collisions Campaign Manager