Bird Migration and Light Pollution: Reducing Urban Mortality

Artificial light at night disorients migratory birds, causing collisions with illuminated buildings and towers. Lights-out programs and building design changes can dramatically reduce this preventable mortality.

Key Facts

An estimated 600 million birds die from building collisions annually in the United States, primarily during migration
Light pollution attracts and disorients nocturnally migrating birds, increasing collision risk with illuminated structures
Chicago's Lights Out program, launched in 1999, was one of the first building-based bird safety initiatives and became a model for other cities
Bird-safe building design including fritted glass, external screens, and reduced exterior lighting significantly reduces collision rates
Fatal Light Awareness Program (FLAP) monitors collision sites in Toronto and advocates for building design changes
Radar-based migration alerts can trigger voluntary lights-out periods during peak migration events
Communications towers with flashing rather than solid red lights show lower bird mortality rates
Glass treatments visible to birds including UV-reflective patterns are effective without affecting human visibility

Welfare Considerations

Light pollution-induced bird mortality is a welfare problem hidden in plain sight: millions of birds drawn to illuminated buildings and dying on impact or falling to die slowly from injuries. The scale is enormous, the cause is known, and the solutions are available. Buildings that implement lights-out programs, bird-safe glass treatments, and exterior lighting reduction prevent deaths measured in thousands per structure annually. The welfare case is clear and the economic case is either neutral or positive when energy savings from reduced lighting are accounted for. What is needed is awareness and the motivation to act on known solutions.

What You Can Do

Advocate for lights-out programs at commercial buildings in your city during peak migration seasons
Apply bird-safe window film or patterns to large glass areas in your home or workplace
Support local bird monitoring groups that document collision mortality and advocate for building design changes
Encourage your employer to implement lights-out and bird-safe glass policies for your workplace building
Participate in Lights Out programs by turning off unnecessary exterior lights during spring and fall migration
Donate to organizations including FLAP and American Bird Conservancy working on bird-safe building standards