Birds Attacking Windows
Not to be confused with window collisions, birds sometimes repeatedly and aggressively fly at reflective surfaces such as windows and mirrors. There are a few steps that you can take to reduce window attacks. Usually, however, the best course of action is to do nothing and wait.
Why Do Birds Attack Windows?
The root of this behavior is territorial. When birds select a nest site, the surrounding area becomes their territory, and they defend it vigorously. Bird territories vary in size depending on the bird species and available resources. A typical suburban songbird such as an American robin needs only a small backyard, whereas a pair of black-capped chickadees will chase off trespassers in a space from eight to 17 acres.
When a bird, searching for a nesting site, accidently sees its image in a reflective surface on its territory, it mistakes it for a rival and tries to drive the “interloper” away. This activity may continue throughout the breeding season, usually from May to early August, often with a pause as the birds move to a new location to start the next brood.
Species that Attack Windows
This behavior is most common in species that frequent suburban yards and nest in the trees and shrubs that surround houses. You may observe it in American robins and northern cardinals, and less commonly in northern mockingbirds, American goldfinches, wild turkeys, and ruffed grouse.
Can Window Attacks Cause Injury?
Despite its violent appearance, this behavior is very rarely fatal. However, birds can sustain injuries, especially to their beaks.
What You Can Do
A territorial bird can be very persistent. If you cover up a window, the bird may search for the perceived rival until it finds another reflective surface. Some people have reported robins attacking as many as 15 windows on both the first and second stories of homes. The best course of action is to be patient and wait for the breeding season to end.
If a bird is attacking a bedroom window and interfering with sleep, cover just the outside of that window. A medium-weight plastic painter's drop cloth, available at hardware stores and home centers, works well—the cloudy plastic will allow light to enter the room but will eliminate reflections. Attach it to the top of the window and allow it to hang freely. Its movement in the breeze will help to scare away the bird.
Beware of methods that don’t remove the reflection. Fake owls and rubber snakes will not deter a territorial bird.
Birds Attacking Cars
Cars have many reflective surfaces, such as side mirrors, bumpers, windows, and chrome grills. If a bird is attacking your car, you can try to eliminate the reflection. Place opaque plastic grocery bags over side mirrors and cover other reflective surfaces with tarps or sheets of opaque plastic. You may also discourage the behavior by moving your car outside of the bird’s territory.
Birds and the Law
Most birds are protected by federal law under the Migratory Bird Treaty Act of 1918. Learn more about birds and the law