Project Safe Flight
Helping Birds Migrate Safely Through New York City
Migrating birds may mistake a dangerous building for a safe resting place. This can occur in two ways. A building that has plants or trees behind glass can actually attract birds. As they fly around looking for food and perches they can injure themselves or even die by crashing into the glass. A second way a building can be perilous to migrating birds is by presenting highly reflective glass near the greenery found in parks large and small. Again, birds see a safe haven where there isn't one, and will collide with the building.
The problem is that birds cannot perceive the solid nature of the glass in either of these situations, and attempt to fly through. Some experts maintain that after habitat destruction, glass poses a greater threat to birds than any other human effect or activity. A conservative estimate puts the number of birds killed annually in the U.S. from striking windows at 100 million. We estimate that anywhere from 90,000 to 230,000 are killed each year just in New York City alone.
The Key Contributors to Bird Collisions
Birds do not detect clear glass as a barrier, nor do they understand reflections in glass. When they see habitat or sky either reflected in glass, or through it, such as in a courtyard, the birds collide at full speed. Many die on impact. New York City, with its skyscrapers and huge swaths of reflective glass, poses a particular threat to over 100 species of migratory birds, some of which are experiencing long-term population declines. Glass is the second-largest direct cause of bird mortality in the U.S.1 (second only to free-roaming domestic cats). Research indicates that across the entire U.S., 365 million to 1 billion birds are killed annually in collisions with windows.
A contributor to the problem of glass is artificial night-time lighting. Many birds, including most songbirds, migrate at night, and artificial light has been shown to attract and disorient them. When point sources of light, such as brightly lit skyscrapers and upward-facing beams, project into these birds' migratory airspace, the birds may be attracted to the glow. They may then be either injured as they flutter confusedly about the lights, or become exhausted and settle in inhospitable areas that make them more vulnerable to collisions. The urban glow from cities along migration routes can cause birds to orient towards and stopover in cities, potentially choosing lower quality habitat and heightening collision risk.
NYC Audubon works to protect birds where the lighting hazard is clear and solvable, such as the Tribute in Light—while our research focuses on achieving a better understanding of the relationship between night-time lighting and bird deaths from collisions.
Seeking Solutions: Project Safe Flight
In 1997, Project Safe Flight founder Rebekah Creshkoff found a dead Common Yellowthroat in the Financial District. Puzzled to find this beautiful songbird in such an unlikely spot, she investigated the problem and soon recruited early volunteers Allison Sloan, Ned Boyajian, and Kellie Quiñones to collect dead birds and monitor several buildings in downtown Manhattan. They discovered a problem much greater than they ever could have imagined. Project Safe Flight was born.
Now over two decades old, it has grown to include several complementary components aimed to reduce bird deaths from window collisions in New York City:
We work with research partners to better understand the impact of artificial night-time lighting on migrating birds, and its relationship to bird deaths from collisions with building glass. Though most collisions occur during the day, the amount of light emitted by a building is a strong predictor of the number of collisions it will cause. Following the recent passage of bird-friendly design legislation, NYC Audubon plans to advocate for legislation requiring a reduction in artificial night-time lighting during spring and fall migration.
Project Safe Flight Resources and References
Bird-Friendly Building Design: Based on NYC Audubon's Bird-Safe Building Guidelines, this 2019 update by the American Bird Conservancy in partnership with NYC Audubon is the most authoritative resource on this issue.
LEED Pilot Credit in Reducing Bird Collisions: NYC Audubon, Bird-Safe Glass Foundation, and the American Bird Conservancy successfully worked with the U.S. Green Building Council to create this pilot credit for sustainable buildings.
Bird Collisions with Windows: An Annotated Bibliography by Chad L. Seewagen and Christine Shepherd
Published Research Cited
1. Loss, S. R., Will, T., & Marra, P. P. 2015. Direct mortality of birds from anthropogenic causes. Annual Review of Ecology, Evolution, and Systematics, 46:99-120.
2. Loss, S. R., Will, T., Loss, S. S., & Marra, P. P. 2014. Bird–building collisions in the United States: Estimates of annual mortality and species vulnerability. The Condor, 116: 8-23.
Additional Published Research
Cabrera-Cruz, S. A., Smolinsky, J. A., & Buler, J. J. 2018. Light pollution is greatest within migration passage areas for nocturnally-migrating birds around the world. Scientific Reports, 8:3261.
Gelb, Y., & Delacretaz, N. 2009. Windows and vegetation: primary factors in Manhattan bird collisions. Northeastern Naturalist, 16: 455-470.
Parkins, K. L., Elbin, S. B., & Barnes, E. 2015. Light, glass, and bird—building collisions in an urban park. Northeastern Naturalist, 22: 84-94.