Reflective Home Windows—Photo: Dee Renee Ericks

Bird Collisions with Glass

Solutions for Home

Birds don’t perceive glass like humans do. Collisions happen when birds fly towards natural reflections in window glass, where they see clouds, sky, or vegetation.

**Juvenile Cedar Waxwing**

Bird-building collisions can happen at any time of the day and year, but tend to increase during migration and when young birds start flying. Therefore, the most crucial times for these measures are during spring and fall migration and in the breeding season.
*Photo: Dee Renee Ericks*

**Stunned orange-crowned warbler**

Many birds that seem fine following a window collision may later die from related injuries. Birds that fly away often suffer concussions and internal injuries. A collision which kills a parent bird may lead to the deaths of babies.
*Photo: Dee Renee Ericks*

**Lights Out**

At night, nocturnal migrants, which includes most songbirds, crash because they fly into lighted windows. Researchers aren’t sure why, but **artificial lights at night also divert and disorient migrating birds**, drawing them into urban areas, which leaves them vulnerable to threats such as building collisions. About 80 percent of migratory birds in North America migrate at night.

Optimal Spacing:

The key to making glass bird-friendly is to create a visible pattern that breaks up transparent or reflective areas of glass. Birds will avoid glass if the markings are tightly grouped, realizing they cannot fit through the transparent or reflective areas of glass.

Vertical stripes or decal placement should be minimum ¼ inch wide with a maximum spacing of 4 inches.

Horizontal stripes or decal placement should be at least ¼ inch wide, maximum spacing of 2 inches.

Tests have shown these dimensions to be the most effective at preventing bird strikes.

Prevention is the best option. Birds need strong clues on or around glass to warn them that it’s there.

Solutions:

For a bird-friendly home, start by identifying problem windows. Not all windows pose equal danger and it can vary with the seasons and changes to sun angle.

To get started, fix:

Windows that have already caused collisions.
Large windows and glass doors, especially those that reflect habitat (including sky).
Windows across from bird feeders, bird baths, and fruit-bearing plants.

Creative Designs:

**PATTERNS ON GLASS**
**Create patterns** on exterior surface of reflective windows. Multiple markings 2” to 4” apart is optimal. A bar of soap, oil-based Sharpie drawings, and tempera paint are excellent markers on glass.
Non-toxic tempera paint patterns or artwork applied to exterior glass can reduce bird collisions for many years. Tempera paint is easily removed using vinegar and water. You can use either a grid pattern of 2 inches by 2 inches, or get creative and paint patterns or artwork on your window.
*Photo: Dee Renee Ericks*

Naturescaping:

**MOVE PLANTS AWAY FROM WINDOWS**
**Birds see house plants through the glass and try to fly to or through them.**
*Photo: Courtesy Nathan Fertig, Unsplash*

**MOVE BIRD FEEDERS AND BATHS far away from (>30 feet) or close to (<3 feet) windows**
*Photo: Glenn Kory/Audubon Photography Awards*

**VISIT:**
**North Olympic Wildlife Habitat Project,** **Backyard Habitat Certification Program** for more information on landscaping for birds.
*Photo by Evan Barrientos/Audubon*

Decals and Window Film:

An easy way to apply the correct spacing of markings across your window: Feather Friendly® small-format or medium-format products

**FEATHER FRIENDLY®** **dot pattern bird tape. The markers are easy to apply, readily apparent on the outside, but are obscure gray markers looking from the inside, out.**
*Photo: featherfriendly.com*

***Bird Divert™*** is tape that features a specially designed pattern that is nearly invisible to humans but highly visible to birds.

CollideEscape™ bird tape and ABC Bird Tape are options.

WindowAlert® ultraviolet decals are only effective when spaced very closely (2”to 4” apart). A single sticker of any shape or size won’t work to prevent strikes.

Note: hawk silhouettes do little to deter birds.

Cords, Shades, and Screens:

**CORDS:**
**Hanging cords, strings or ribbons in front of your windows can be effective and unobtrusive.**
*Acopian BirdSavers*™known as “zen curtains,” are closely spaced cords that hang down over windows. They do the work of tape or decals but are easier to install and can be aesthetically pleasing. **Make them yourself (DIY), or order custom-made based on the size of your window(s).**
*Photo: Cornell Lab*

**INSTALL EXTERNAL SCREENS**
**External insect window screens reduce bird collisions by minimizing window reflections and alerting birds that windows are barriers.**
*Photo courtesy Darrin Henein, Unsplash*

**CLOSE BLINDS**
**Blinds, or curtains can help break up exterior reflections.**
***Photo courtesy*** ***Ruan Richard Rodrigues***, ***Unsplash***

A local source for some of the products mentioned above is Wild Birds Unlimited® located in Gardiner, Washington. They currently carry the UV paint pens called WindowAlert® UV Liquid, WindowAlert® ultraviolet decals, and Feather Friendly® tape. Contact them at (360) 797-7100 to check for availability.

(Note: No window product can guarantee elimination of window collisions. Results will vary depending on local bird populations, landscape conditions, product used, and building design. We are providing these product suggestions as a convenience, and there are many more that may work in a similar way to suit your needs.)