Apply markings in a dense pattern, leaving no gaps more than 5 cm by 5 cm (2 inches by 2 inches). If gaps are any larger, birds may try to fly through them and still hit the window.
Bird-Safe Window Marker Guidelines
Although there are many products on the market that claim to stop birds from hitting windows, many do not live up to their promises. Fortunately, by following a few simple guidelines, you can choose an effective option to avoid hearing that dreaded ‘thud.’
The key to stopping birds from flying into your windows is to make the entire window look like a barrier to birds. You can do this by applying dense patterns of markings (small dots, squares, lines, etc.) to the outside of your window. To be most effective, markings must meet these guidelines:
Apply markings to the outside surface of the glass, NOT the inside. Reflections of trees or sky on the outside of the window may render any internal window markings invisible.
Markings must be of high contrast so that they stand out on the window. Markings with poor contrast, for example black dots on a very dark window, might not be noticed by birds.
Each marking should be no less than 6 mm (1/4 inch) in diameter.
Markings must cover the entire surface of the glass.
Bird-Safe Window Options
There are a variety of attractive and affordable options to stop birds from hitting windows at your home or cottage, without affecting your view.
Here are just a few.
Decorative and Privacy Window Films
Frosted or decorative window films can be an attractive addition to your windows, while also helping birds to avoid a deadly collision with glass. Wallpaper for Windows is one company which offers an assortment of decorative window films. Look for a design that meets FLAP Canada’s Guidelines for Visual Markers or contact your local signage company. They may be able to do custom designs to create an attractive and bird-safe treatment. See what one homeowner did on the FLAP blog.
Perforated Window Film
Perforated window film creates an opaque surface on the outside of the glass that looks like a solid barrier to birds. However, the thousands of small perforations in the film let in ample light and permit a view of the outdoors from inside your home. These types of products come in a wide variety of colours and can be custom-printed with images. To keep birds safe, avoid using transparent (‘clear’) products. Although there are many perforated window films available, CollidEscape is one product marketed specifically to reduce bird collisions with glass.
Feather Friendly DIY Tape
Feather Friendly DIY tape leaves rows of white dots on your window so birds will understand a barrier is present. When installed according to the instructions, this product can be very effective at preventing window collisions. You can order Feather Friendly DIY Tape online, or purchase at many Wild Birds Unlimited and Lee Valley stores. Read our how-to guide about how to install Feather Friendly.
*Need help installing Feather Friendly on your home windows? Consider contacting your local window cleaning company or handyman.
Ribbons or String
Ribbons or string hung on the outside of the window can be an effective collision deterrent if they are spaced no more than 10 cm (4 inches) apart and run the entire length of the window. Consider spacing the strands even closer at 5 cm (2 inches) to meet FLAP Canada’s Guidelines for Visual Markers. You can order this type of product custom-made for your windows, or you can easily make your own.
Tape
You can make your window look like a barrier to birds by applying lines of tape across the outside surface of the window. To be most effective, do not leave any gaps of more than 5 cm (2 inches) between the strips of tape. You can buy special rolls of tape intended specifically for the purpose of stopping birds from hitting windows (but do not use ‘clear’ products).
Decals
Falcon silhouettes have long been a popular approach thought to stop birds from hitting windows, but they are often ineffective unless installed properly. The silhouette does not make smaller birds avoid the area, and people often place just one or two decals on large windows, leaving most of the glass untreated and dangerous. If you choose to use decals, you can use any shape you like, but they must form a dense pattern on the outside of the window and not leave any gaps more than 5 cm or 2 inches.
Window Grilles
Decorative or security window grilles on the outside of the window can appear as a barrier for birds to avoid. For best results, assure that the bars or patterns do not leave gaps greater than 5 cm or 2 inches.
Exterior Shades or Solar Screens
Motorized or permanently fixed solar screens or shades that cover the outside surface of the window are another way to stop birds from flying into windows, while also offering privacy and climate/lighting control. However, they may affect your view and they will only prevent birds from hitting windows when drawn. Please note that drawing interior curtains or blinds is not an effective option to prevent birds from hitting windows, because it does not address reflections on the outside surface of the glass.
Exterior Window Screens
The product Bird Screens is a special window screen that you mount on the outside of your window. The purpose of the screen is to form a flexible barrier between birds and the glass to soften the impact and reduce the chance of injury if a bird does fly towards the window. Regular exterior mounted window screens may also provide some level of protection, but there is still a chance of injury if the screen is mounted too close to the glass or is too taut.
Important note on UV treatments: Although there are UV products available on the market (e.g., WindowAlert), there is not enough scientific evidence to show that they are widely effective. FLAP Canada recommends choosing an alternative method until we know more.
Disclaimer: Results may vary depending on conditions such as landscaping, topography, building design, lighting, local bird populations, and the condition of the product itself. No window treatment can guarantee elimination of bird-window collisions.
Replacement Windows and New Builds
If you are planning to replace an entire pane of glass or build a new house or cottage, consider choosing bird-safe glass with built-in window markings. Here are just a few options. Visit birdsafe.ca for more information.
Frit and Acid-Etched Patterns
Ceramic frit and acid-etched patterns that meet FLAP Canada’s Guidelines for Visual Markers can be an attractive and effective option to stop birds from flying into windows. Certain treatments may serve additional purposes of providing privacy or reducing the transmission of light and heat.
Opaque and Frosted Glass
Full-coverage opaque and frosted glass are potential options to reduce the risk of window collisions, provided the outside surface of the glass is treated. If you are applying frosted patterns to glass, assure they meet FLAP’s Guidelines for Visual Markers. However, you should keep in mind that glass with a frosted exterior surface can be a bit difficult to keep clean.
Window Muntins
Muntins are metal or wood dividers in a window that separate panes of glass. Windows can be custom created with closely spaced exterior muntins, but generally these are spaced no closer than 6 x 6 inches. Although 6 x 6 inch spacing does not meet FLAP Canada’s Guidelines for Visual Markers, it may provide better protection than a completely untreated window. To make it most effective, you can still add additional visual markers between the gaps.
Temporary Solutions
Sometimes you need a quick fix while you work towards a more long-lasting solution. If you choose one of these methods, you may need to reapply the treatment after it rains and after you wash your windows.
Patterns with Tempera Paint or Paint Pens
Treat your windows like a canvas and be artistic! Draw or paint your own unique patterns on the outside of your window, making sure not to leave any gaps greater than 5 cm or 2 inches. Watch our how-to video on preventing window strikes using washable tempera paint.
Soap
A bar of soap is the ultimate quick fix. Draw patterns on the outside of the glass with the bar and reapply as needed. Check out our how-to video.
Whitewashed Windows
Whitewashed windows will appear as a complete barrier to birds. This method also provides privacy and prevents a building from overheating, while still allowing light in.
Guidelines on Bird-Feeder Placement
If you feed birds, move your bird-feeder (and other bird attractants like bird baths) as close to the window as possible (half a meter or closer). If a bird leaving the feeder accidentally flies into your window, it is less likely to build up enough momentum to seriously injure itself over this short a distance.
What Do Homeowners Have To Say?
DIY Building Risk Assessment App
“I have so many windows! Which ones should I treat first?”
Certain windows will pose a greater threat to birds than others. To help you identify which windows are most important to treat first, take the BirdSafe® self-assessment for homeowners or use the FLAP app. Treat the most dangerous windows first.