Birds flying into windows is a common and often distressing event that can lead to injury or death for birds. Understanding why these collisions happen, how to prevent them, and how to respond when they do occur can help protect local bird populations.
Why Birds Collide with Windows
Birds frequently collide with windows primarily due to reflections and transparency. Windows reflect the surrounding environment, such as trees, sky, or distant landscapes, making them appear as open space or a continuation of habitat. Birds perceive these reflections as safe flight paths, not recognizing the solid glass barrier.
The transparent nature of glass is another reason for collisions. Birds often cannot perceive clear glass as a solid obstacle, especially when they see through a building to vegetation or open space on the other side. This creates a “tunnel effect,” leading birds to attempt to fly straight through the perceived opening. Unlike humans, birds’ vision is not adapted for discerning transparent surfaces or reflections.
Bright indoor lights at night can also disorient birds, especially during migration. Migratory birds often travel at night, relying on natural light sources for navigation. Artificial lights can interfere with their ability to navigate, drawing them towards lit structures where they may collide with windows. Poor weather conditions, like fog, can increase this risk.
How to Prevent Window Collisions
Making windows more visible to birds is the most effective way to prevent collisions. Window decals or stickers applied to exterior glass break up reflections and provide visual cues. For effectiveness, space markers two to four inches apart, as birds can fly through smaller gaps. UV-reflective coatings or patterns on films, visible to birds but less noticeable to humans, are also available.
External screens or netting provide a physical barrier, softening the impact or preventing birds from reaching the glass. These are effective on windows known for frequent strikes. Adjusting internal window treatments, like closing blinds or curtains, reduces transparency and reflections, especially when interior lights are on.
Bird feeder placement influences collision risk. Placing feeders either very close (within 3 feet) or very far (over 30 feet) reduces high-speed impacts. Close feeders prevent birds from building momentum for severe injury. DIY solutions like painting patterns with tempera paint or using soap streaks can serve as temporary visual deterrents.
What to Do if a Bird Hits Your Window
If a bird hits your window and appears stunned, observe it from a distance. Birds are often temporarily disoriented and recover within minutes to an hour. Provide space and ensure the area is safe from predators.
If the bird is visibly injured, bleeding, or does not recover after a couple of hours, it may need professional help. Gently place it in a dark, quiet, well-ventilated container, like a shoebox, to reduce stress. Do not give it food or water. Contact a local wildlife rehabilitator for guidance; they provide appropriate care and can be found online or through animal shelters.