Migratory Bird Welfare: Window Strikes, Cats, and Artificial Light

Human infrastructure causes millions of migratory bird deaths annually through window strikes, feline predation, and light pollution that disrupts navigation.

Key Facts

Bird-window collisions kill an estimated 600 million birds annually in the United States alone
Migratory birds navigate using stars and are disoriented by artificial light that causes building collisions during night migration
Lights Out programmes in major cities during peak migration have significantly reduced collision mortality
Window bird strike prevention products including UV-reflective patterns are effective but poorly adopted
Domestic and feral cats kill an estimated 1.3-4 billion birds annually in the United States
Reflections of habitat in large windows cause birds to attempt to fly through what appears to be continuous habitat
New building designs that incorporate bird-safe glass are being required in some jurisdictions
Citizen science programmes including eBird migration tracking inform the timing and location of peak risk periods

Welfare Considerations

Migratory bird welfare from human infrastructure impacts involves individual-level acute trauma from window strikes and predation combined with population-level effects from mortality that removes millions of individuals from breeding populations each year. A bird killed by a window strike experiences rapid physical trauma that is at minimum acutely painful if not immediately fatal. The mortality is largely preventable through interventions that either reduce the visual confusion that causes strikes or reduce the exposure of migrating birds to the most dangerous infrastructure at the most dangerous times. Individual action through window treatment and cat management is accessible to anyone, while collective action through building codes and urban light management requires policy change that can address the problem at scale.

What You Can Do

Apply bird-safe window treatments including UV-reflective decals or screens to windows with high strike risk
Participate in Lights Out initiatives by turning off or dimming unnecessary building lights during peak migration seasons
Keep domestic cats indoors particularly during peak spring and autumn migration periods
Report bird window strikes to citizen science databases to contribute to collision risk mapping
Advocate for bird-safe building design requirements in planning regulations for new construction