There are a few potential reasons why a bird may be attacking your window:
Territorial Behavior
During breeding season, male birds can become very territorial. They attack windows because they see their reflection in the glass and think it’s another bird intruding on their territory. The bird is trying to scare away what it perceives as a competitor. This is most common with robins, cardinals, mockingbirds, and other backyard birds. The attacks tend to be concentrated in spring, as birds are establishing nesting sites and attracting mates.
Nest Protection
If the window is near where a bird has a nest, either in a tree or on the side of your house, it may attack as it tries to protect its eggs and offspring. The bird sees its reflection and thinks another bird is too close to the nest, so it takes aggressive action to defend its young. Nest protection is another cause of increased window attacks in spring.
Confusion
Birds can sometimes accidentally fly into windows when they don’t see the glass. If this happens once, the bird associates that window with danger and may attack it in the future thinking it’s an enemy. This most often happens with larger picture windows that reflect trees or the sky that birds may try to fly into.
How to Stop Birds From Attacking Windows
If a bird constantly attacking your window becomes a nuisance, there are several effective techniques you can try to deter the behavior:
Use Decals and Reflective Tape
Placing decals, stickers, or reflective tape strips on the outside of windows can help break up reflections. This prevents the bird from seeing its reflection clearly and removes the illusion that another bird is intruding. Distancing decals a couple inches apart across the window works best.
Install External Screens
An exterior screen over the window stops the bird’s reflection and prevents it from hitting the glass. This is the most effective physical barrier. Make sure the screen has a tight mesh size so the bird cannot trap itself between the screen and window.
Use Predator Silhouettes
Cutouts of hawks, owls, or snakes attached to the outside of windows can frighten territorial birds. The predator shapes make them cautious to avoid the area. Just the silhouette works as birds recognize the shape instinctively.
Scare Devices
Objects like wind chimes, aluminum pie pans, and predator decoys near the window that move in the wind and make noise can startle birds and convince them to stay away. Anything that makes the window appear intimidating and dangerous will deter attacks.
Anti-Reflective Glass
New windows with an etched or frosted glass surface diffuse and eliminate reflections. Installing these specially designed windows can prevent future bird strikes, but is an expensive option. Anti-reflective window film achieves similar results at a lower cost.
Why Do Birds Attack Specific Windows?
There are some common factors that cause birds to repeatedly attack the same window:
– Windows that reflect prominent trees, branches, bird feeders, or bird baths that a bird may be defending as its territory.
– Large picture windows and bay windows that birds may try to fly directly into. The expansive glass reflects the sky and trees that birds naturally want to fly towards.
– Windows near nests and feeders where the bird spends the most time and is highly protective.
– Isolated windows on homes surrounded by open land or foliage that intrude into the bird’s environment.
– Windows that the bird can see its reflection clearly in contrast to the surrounding landscape.
Territorial Birds
Species known for aggressively defending territories around nesting sites like robins, cardinals, mockingbirds, blue jays, and hummingbirds are most prone to prolonged window attacks.
Migrating Birds
Migrating birds getting ready for long flights can strike residential windows in unusual locations and with increased frequency. Pre-migratory hyperactivity may reduce awareness and lead to confusion.
Nesting Location
Attack intensity is highest on windows closest to the bird’s nest, and most prevalent during mating and offspring rearing seasons. Females are especially aggressive while incubating eggs.
Reflection Intensity
Windows that offer a vivid reflection due to lighting contrast with the surrounding area pose the greatest risk. A darker interior behind a bright window prevents seeing through to the inside.
Preventive Measures
To make your windows “bird-friendly” and avoid attacks in the future:
Mark the Outside Glass
Apply decals, tape, or tempera paint to the exterior surface. Placing markings on the outside is more effective than the inside. Space markings no more than 2-4 inches apart for optimal visibility. Vertical stripes work better than horizontal.
Eliminate Food Sources
Prevent bird attacks by removing feeders and birdbaths within 30 feet of windows. Limit food sources near home to discourage territorial behavior.
Reduce Reflections
Close blinds, curtains, or external shutters when possible. Install external screens, sun shades, or awnings to make windows less reflective. Keep lights off inside to reduce contrast.
Set Up a Buffer Zone
Avoid placing bird attractors like plants, trees, feeders, and baths too close to windows. Leave a 2-3 foot gap between the window and other objects. Trim back branches to control reflections.
Consider One-Way Film
Special window films allow you to see out, but block external visibility and reflections. From the outside, the window appears frosted, opaque, or mirrored. Films come in various transparency levels.
Conclusion
Birds attacking windows are trying to defend a nest or territory from what they perceive to be an intruder in the form of their reflection. Several techniques like exterior screens, scare devices, and window films can effectively deter this behavior. To prevent attacks in the future, limit reflections with window markings, control food sources, and keep attractors away from glass. With some simple modifications, you can have a bird-friendly home.
Frequently Asked Questions
Why do birds only attack certain windows?
Birds tend to repeatedly attack windows where conditions make them more likely to see their reflection. This includes large picture windows, windows aligned with trees/branches, windows near nests or feeders, and windows where interior/exterior light contrasts create a vivid reflection.
Will birds attack windows at night?
Bird attacks typically happen during the day since they rely on visual cues. Nocturnal species may potentially strike lit windows at night if exterior lights create reflections. Most incidents occur during daylight hours when birds are active.
How long will birds attack my window?
Attacks can persist for days, weeks, or even months through multiple seasons if the bird continues to see its reflection. Territorial species are likely to attack for longer periods. Discouraging the behavior as soon as it starts is most effective.
Do homemade remedies like hawk silhouettes work?
Hawk silhouettes, owl decoys, aluminum foil strips, and similar homemade deterrents can discourage window strikes when moved frequently and combined with other techniques. Used alone, birds eventually recognize they are not real predators.
When are birds most aggressive towards windows?
Bird attacks increase in frequency during breeding season and peak in the spring. Males defend territory aggressively through summer while females are territorial near their nest. Attacks diminish in winter but may still occur near feeders.
Comparison of Bird Deterrent Techniques
Method | Effectiveness | Cost | Convenience |
---|---|---|---|
Decals/Tape | Moderate | Low | High |
Screens | Very High | High | Low |
Scare Devices | Moderate | Low | Moderate |
Anti-Reflective Glass | Very High | Very High | High |
Window Films | High | Moderate | High |
This table compares different methods to deter bird window strikes in terms of effectiveness, cost, and convenience. Screens rank highly effective but expensive and permanent. Films offer a good balance of deterrence and practicality. Homemade scare devices are cheap but require ongoing effort. Overall, a combination of techniques works best.
Further Reading
Bird-Friendly Window Treatments
To explore bird-friendly window solutions in more depth, check out these additional resources:
– American Bird Conservancy Guide to Bird-Friendly Windows – Provides a detailed overview of various treatment options, pros/cons, and DIY installation tips.
– Cornell Lab of Ornithology Window Collisions Deterrence Methods – Summarizes extensive research on techniques to prevent collisions and reduce mortality.
– Bird Screen – Sells screens designed specifically for excluding birds from enclosed spaces like patios and pools.
– Feather Friendly – Certifies window films and treatments that meet standards for reducing bird strikes. Lists certified products.
– BirdCrash.org – Nonprofit group focused on reducing building collisions through design and policy. Many window remediation resources.
Bird Behavior and Biology
To learn more about the underlying bird behavior and biology behind window attacks:
– The Cornell Lab Bird Academy – Free online courses on bird biology topics like reproduction and migratory instincts.
– Birds Attacking Windows: Solving the Problem – Audubon article explains causes from the bird’s perspective.
– Why Birds Hit Windows—And How You Can Help Prevent It – Smithsonian article with bird vision insights on strike factors.
– Window Collisions by Birds – Scholarly research on correlates and seasonality of collision incidents.
Gaining a better understanding of the forces driving birds to attack windows can help inform effective deterrent solutions tailored to specific situations.