The New York City Skyline at night. Photo: Adriano BIDOLI/CC BY-NC-ND 2.0
Protecting Migratory Birds from Artificial Light
Every spring and fall, millions of birds—many of them songbirds—migrate at night through New York City. They navigate using star maps, physical landmarks, and even the Earth's magnetic field, possibly even "seeing" its lines in dim blue light. But our city's artificial light at night may obscure the birds' sense of the magnetic "guidelines," drawing them off course from their natural roadmap and into dangerous urban environments. The good news? Turning out lights is a simple yet powerful action that can save countless lives.
How Light Impacts Bird Collisions
The majority of collisions with buildings take place in the daylight, but the birds are drawn to these unsafe environments by night-time lights: the amount of light emitted by a building is a strong predictor of the number of collisions it will cause, more so than building height. The urban glow of cities along migration routes can actually cause birds to orient towards and stop over in cities. 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.
When dawn comes and hungry birds look to refuel for their long journeys ahead, they encounter a confusing urban landscape full of glass windows and facades that reflect sky or habitat, often colliding as they seek refuge or escape.
Understanding Artificial Light: Our Scientific Research
We actively engage in scientific research to understand exactly how artificial light impacts migratory birds and to find the most effective solutions:
Academic Partnerships: We collaborate with leading institutions like the Cornell Laboratory of Ornithology and the University of Delaware. Our research partnerships investigate the correlation between migratory bird density and the intensity and quality of nighttime artificial light. This data, combined with our extensive collision records, helps us pinpoint high-risk areas and develop targeted strategies.
Tribute in Light Monitoring: NYC Bird Alliance staff and volunteers have monitored the Tribute in Light memorial since 2002 to ensure that while we honor those lost to us on September 11, 2001, unnecessary harm does not come to thousands of migrating birds who are attracted to the Tribute’s powerful lights and get stuck circling within its beams. This has helped advance our understanding of the impacts of artificial light on night-time migrating birds.
To reduce risks to migratory birds from artificial light at night, turn off all exterior floodlights, spotlights, and decorative, vanity, and event lighting in your building from 11pm until 6am during the heights of migration—April 1 through May 31 and August 15 through November 15. While these dates represent the largest risk for birds, we suggest turning off all of these lights throughout the year.
Here are some practical solutions to help reduce light pollution:
Turn off lights at night on unoccupied floors and in unused spaces.
Opt for shielded lighting that directs lights downward.
Install automatic motion sensors and controls wherever possible.
Use task lighting at your workstation after hours instead of overhead lights.
Close curtains and blinds.
Lights Out Rally at City Hall. Photo: NYC Bird Alliance
Advocate for City-Wide Change
Your voice is crucial in pushing for broader, systemic change across New York City. We successfully advocated for a law requiring city-owned buildings to turn off nonessential outdoor lights during peak migration. We continue to work towards similar bird-friendly lighting legislation for privately owned buildings.
Learn more about the effects of night-time lighting on bird migration in Bird-friendly Building Design, our joint publication with American Bird Conservancy.
Discover how our annual Tribute in Light monitoring is deepening our understanding of artificial light's impacts on birds.
Report a bird collision to our crowdsourced database, dbird.org, to contribute to our collisions research.