Working to prevent millions of birds from fatal collisions with windows

October 2, 2023

Four American redstarts were recently admitted to the von Arx Wildlife Hospital at the Conservancy of Southwest Florida after being injured from collisions with windows and lanai screens, a leading cause of bird mortality in the United States.

Female American redstart
Female American redstart injured from window strike

All four redstarts were found in different areas of Collier County and suffered serious neurological damage. Staff administered arnica tincture (a homeopathic remedy often used in trauma cases) and placed the injured birds on supplemental oxygen in darkened animal intensive care units. As the neurological deficits resolved, the redstarts were moved to a larger indoor flight space to rebuild strength. All four were cleared for release after several days of care.

Colliding with windows is a leading cause of bird mortality in the United States. It is estimated that approximately one billion birds die annually from collisions with buildings and windows in the United States. Additionally, because screened lanais are so common in Florida, impacts with screening are also a frequent cause of injury for migratory birds in our area. Collisions can occur both at night and during the day.

Environmental Studies Dormitory from outside at night
Environmental Studies Dormitory, featuring new bird-friendly patterned glass

At night, lights on office buildings draw migratory birds close to buildings where birds can become disoriented and exhausted, causing them to collide with the buildings. Many cities across the United States and Canada are working to save migratory birds by initiating “lights out” programs during peak migration time. These programs are similar to the “lights out” programs that exist along our coast during sea turtle nesting season.

Collisions during the day occur because birds can’t perceive clear or reflective glass. Windows reflect the sky and trees and birds perceive this as an open flyway and strike the glass, often at a high rate of speed. These collisions happen when birds strike windows or doors on residential and commercial buildings.

The key to preventing window strikes is to make birds aware of expanses of glass. Many options exist that successfully prevent birds from colliding with residential and commercial windows. In fact, the Conservancy recently finished construction on our new Environmental Studies Dormitory. Utilizing bird-friendly patterned glass was always a priority, starting with the initial building designs. Staff researched window options and the Environmental Studies Dormitory now serves as an example for other construction projects in the community.

View of new dormitory windows from inside building
View from inside the patterned glass windows in the Environmental Studies Dormitory
Outside of dormitory patterned glass door
View from outside the patterned glass windows in the Environmental Studies Dormitory

Designing functional, cost-effective, attractive buildings that kill few to no birds is possible. Migratory birds face so many dangers, but preventing collisions with windows is something every homeowner and business can do that could potentially save millions of birds’ lives every year. Visit or for detailed information on techniques that will eliminate the reflectiveness of windows and solutions that will prevent birds from colliding with windows.

If you find a bird that has struck a window, place the bird in a ventilated box immediately. A stunned bird is an easy target for roaming cats or other predators. In addition, when a bird is stunned and disoriented, it can easily injure itself further by stumbling or fluttering into a road or swimming pool. Do not offer any food or water — bring the bird to the von Arx Wildlife Hospital for professional medical attention as soon as possible.