By Sara Dollen, Animal Care Technician, Sity Wildlife
Each spring and fall, billions of migratory birds take to the skies of North America. In the United States alone, approximately one billion birds die from collisions with windows, buildings, and other human-made structures every year. At City Wildlife, nearly one in five of our annual patients are window strikes. Most arrive with peak migration, approximately April–May and September–October, where we may admit more than 20 collision victims in a day.
Why do birds collide with buildings?
The reflectiveness and transparency of glass are the primary culprits, often compounded by indoor plants, mirrored walls, or converging glass facades. At night, artificial lighting becomes a deadly lure: over 80% of migratory birds travel after dark, and light pollution traps them in fatal spirals of disorientation and exhaustion. In Washington, D.C., species such as White-throated Sparrows, Ovenbirds, Common Yellowthroats, and American Woodcocks are frequent victims.
How City Wildlife responds
Our work rests on three pillars: monitoring, rehabilitation, and advocacy. Lights Out DC volunteers record casualties and rescue stunned survivors. Meanwhile, our rehabilitation team provides medical care to survivors, commonly treating concussions, corneal ulcers, and pulmonary trauma. Even birds that seem uninjured are monitored for at least 48 hours, as hidden injuries often emerge later. Through social media, we also raise awareness, encourage simple protective actions, and mobilize direct support for treating window strike victims. Despite the scale of the challenge, progress is being made. Data from Lights Out DC has already influenced policy, while partnerships with local organizations are helping us expand “lights out” pledges among property managers. Every step from an individual installing window decals at home to legislation mandating bird-safe architecture helpsreduce the staggering toll of collisions.
What You Can Do
Everyone can play a role in protecting migratory birds:
–Make windows bird-safe. Apply screens or anti-collision decals 2” x 2” apart to the outside of windows.
–Reduce light pollution. Turn off non-essential lights at night, especially during migration. For essential lights, follow Dark Sky International’s five principles for Responsible Outdoor Lighting at Night.
–Keep feeders and plants away from untreated glass to reduce collision risks.
–Rescue responsibly. If you find a bird that has struck a window, place it gently in a paper bag or box in a quiet, dark place with no food or water and bring it to a licensed rehabilitator like City Wildlife.
–Report collisions. Share sightings with Lights Out DC or national databases such as dbird.org to help track patterns and advocate for safer buildings.
