Imagine your windows as invisible barriers to birds. These transparent panes, often reflecting inviting landscapes or seeming to offer a clear passage through, tragically become deadly obstacles. It’s a widespread problem: studies estimate that window strikes cause up to a staggering one billion bird deaths in the U.S. annually. This concerning statistic, highlighted in a 2014 study published in The Condor: Ornithological Applications, underscores the urgent need for effective solutions.
american goldfinch killed by window strike
Fortunately, making your home safer for birds is easier than you might think. Christine Sheppard, who leads the Bird Collisions Program at the American Bird Conservancy (ABC), emphasizes that simple actions can significantly reduce the danger your windows pose. The ABC website offers comprehensive resources on preventing collisions, and organizations like the Fatal Light Awareness Program (FLAP) also provide valuable information.
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The impact of window collisions can be devastating for birds. Even if a bird appears to recover after hitting a window and flies away, the collision can cause fatal internal injuries. Daniel Klem, a researcher at Muhlenberg College who has studied bird-window collisions extensively since the 1970s, poignantly describes glass as “an indiscriminate killer,” affecting both healthy and vulnerable birds alike.
Why Birds Collide With Windows
Bird collisions with windows happen for a couple of primary reasons, categorized by time of day: daytime and nighttime collisions.
During the day, the main culprit is reflection. Birds are deceived by reflections of trees, bushes, and the sky in the glass, perceiving these reflections as real habitats they can fly into. Alternatively, they might see right through the window to indoor plants or vegetation on the other side, believing it’s an accessible pathway.
imprint of dove on plate glass window
At night, the danger shifts. Nocturnal migrating birds, which include the majority of songbirds, are particularly vulnerable to lighted windows. Artificial lights disorient these birds during their nighttime migrations, especially in foggy or low-ceiling conditions. Drawn to the illuminated areas, they can become confused, circling around lights and colliding with structures, including brightly lit windows. Compounding the issue, birds attracted to urban lights might find temporary roosting spots, only to face the daytime hazard of window reflections the following day. Projects like BirdCast and the Fatal Light Awareness Program (FLAP) offer further insights into the impact of light pollution on bird collisions.
Another, less common reason for window strikes is territorial behavior. Especially during the spring breeding season, birds may see their own reflection in a window and mistake it for a rival, leading them to attack the reflection. While this behavior can be bothersome, it rarely poses a serious threat to the bird, and the window safety measures outlined below can usually deter this as well.
How to Safeguard Your Windows For Birds
The first step in making your windows bird-safe is to identify the most hazardous ones. Pay close attention to large picture windows, corner windows where two panes meet at right angles, and windows located near bird feeders. To assess the danger, step outside your house and look at your windows from a bird’s perspective. If you see reflections of trees, sky, or greenery in the glass, or if you can see through the window to vegetation inside or beyond, these are potential collision points.
reflection of foliage in window – hazard to birds
Contrary to older advice, the distance of bird feeders from windows is now considered less critical than making the windows themselves bird-friendly. As Christine Sheppard from the American Bird Conservancy notes, “If you’ve got windows near a bird feeder, you should make them bird friendly and don’t worry about how far away they are.”
Treatments for Existing Windows
For existing windows, several effective treatments can significantly reduce bird collisions. The key principle is to make the glass visible to birds. For smaller birds, markings should ideally be spaced no more than 2 inches apart across the entire exterior surface of the window. Acopian BirdSavers, using hanging paracords, can be spaced slightly wider at 4 inches due to their increased visibility. Crucially, all treatments must be applied to the outside of the window.
Tempera paint or soap
A simple and budget-friendly method is to use tempera paint or soap to mark the exterior of your windows. You can create a 2×2 inch grid pattern, or get creative with patterns or artwork. Tempera paint is both inexpensive and durable.
Decals
Applying decals, stickers, sun catchers, mylar strips, masking tape, or even sticky notes to the outside of your windows can be effective, but only if they are spaced very closely together. It’s important to remember that hawk silhouettes alone are not effective deterrents. A few scattered stickers on a large window will not prevent collisions; you need to cover a significant portion of the glass surface with narrow gaps between markings to be truly effective.
Dot Patterns and Tape
For a more long-lasting and precisely spaced solution, specialized tapes with dot patterns are available. Products like those from Feather Friendly are designed specifically for bird collision prevention and ensure correct spacing for optimal effectiveness.
Acopian BirdSavers
Also known as “zen curtains,” Acopian BirdSavers consist of closely spaced cords that hang vertically in front of windows. They function similarly to tapes or decals but are easier to install and can be aesthetically pleasing. These are highly effective and are used at the Cornell Lab of Ornithology headquarters to protect their windows. You can purchase pre-made BirdSavers or even make your own following DIY guides available online.
Screens
Installing mosquito screens over your windows is a highly effective method, provided they are mounted on the exterior and cover the entire window surface.
Netting
Covering the outside of the glass with netting, positioned at least 3 inches away from the window surface and pulled taut, can effectively bounce birds away before impact. Small-mesh netting (around 5/8″ or 1.6 cm) is recommended to prevent birds from becoming entangled while still providing a safe barrier. Netting can be easily installed and removed by mounting it on a frame, such as a storm-window frame.
One-way transparent film
Specialized window films like Collidescape are designed to be one-way transparent. From the inside, you maintain your view, but from the outside, the window appears opaque to birds. These films can also offer the added benefit of reducing incoming light, potentially lowering cooling costs.
New Homes and Remodels
If you are building a new home or renovating, you have the opportunity to incorporate bird-friendly designs from the outset:
Shutters
Install exterior shutters and keep them closed when rooms are unoccupied or when you don’t need natural light or the view. Shutters also offer significant energy-saving benefits.
Sun shades or awnings
Exterior sun shades or awnings effectively block sunlight reflections. Remote-controlled options provide added convenience.
External screens on new windows
When choosing new windows, consider models that integrate screens across the entire exterior glass surface.
Interior blinds
Adding interior vertical blinds and keeping the slats partially closed can also help to break up reflections.
Avoiding visual paths
Be mindful of interior layouts that create the illusion of open pathways. For example, a bright window directly opposite a picture window can create a perceived clear route through your house. Closing interior doors or using window shades to block these visual paths can be helpful.
Lights Out
“Lights Out” initiatives are gaining momentum in cities across the U.S., including major urban centers like New York City, Dallas, Houston, and Philadelphia. The pervasive nighttime glow from office buildings and streetlights in urban areas is particularly hazardous for migrating birds, drawing them off course, delaying their migrations, and increasing their vulnerability to window collisions. Participating in “Lights Out” initiatives by turning off non-essential lights and using downward-facing lighting are simple yet impactful steps to reduce light pollution and protect migrating birds. Even with city-wide efforts, taking window collision precautions at home remains crucial.
How to Help a Window Collision Victim
If you find a bird that has collided with a window, immediate action can significantly improve its chances of survival. Even seemingly unharmed birds may suffer from internal injuries. Promptly contacting a wildlife rehabilitation facility is the best course of action.
If you find a dazed bird:
- Capture and contain it: Approach the bird gently from behind and use both hands to cup it carefully. It might flutter or chirp, but remain calm. Handle small birds with utmost care, ensuring your grip is gentle but secure, without squeezing.
- Find a suitable container: Place the bird in an unwaxed paper bag or a small cardboard box lined with tissue paper or paper towels to provide grip. Keep the container in a dark, quiet, and warm place away from children and pets.
- Do not feed or water the bird: Avoid handling the bird further to minimize stress, as wild birds perceive humans as potential threats.
- Find a rehabber: Use online directories like the Humane Society’s wildlife rehabilitator finder to locate a licensed wildlife rehabilitator near you. Contact them for guidance and instructions. They may be able to arrange transport if you cannot bring the bird to them.
- Release if instructed: If the rehabilitation facility advises you to release the bird, take it to a wooded area or suitable habitat away from buildings. Before releasing, observe its flight ability. Point the container towards vegetation, open it slowly, and allow the bird to fly out. If it doesn’t fly strongly, recapture it and contact the rehab facility for further advice.
By taking these preventative measures and knowing how to assist injured birds, you can make a real difference in protecting our feathered friends from the dangers of window collisions. Let’s make our homes and cities safer havens for birds.
