Birds cannot recognize that reflective and transparent glass is a solid object. To help reduce bird collisions, we need to provide birds with visual cues that a barrier is present. There are a wide variety of attractive and cost-effective options on the market to reduce the likelihood of birds hitting windows.

  • TIP: Explore cost-neutral solutions by looking for products that can serve additional purposes as privacy, artwork, branding, advertising, or energy savings (e.g., customized solar reflective films with bird-safe markers).

Integral applications: Frit and acid-etched patterns

Ceramic frit or acid-etched designs on the first surface (the outermost surface) of the glass can be bird-safe if they meet current bird-safe standards (i.e., CSA standard). These methods are useful primarily for new construction or replacement of entire panes and are generally available in a variety of attractive patterns. Before selecting a product, ensure it has a reasonable warranty.

These are a few glass manufacturers that offer first surface applications.

First surface acid-etched patterns

First surface ceramic frit

Etched glass on commercial building

Acid-etched glass. Photo: Walker Glass

Applied coverings: Patterns or window films

Glass can have an image or pattern applied to the exterior glass surface. Markers can be of any shape or pattern, but they must meet current bird-safe standards (i.e., CSA standard). Any exterior treatments must withstand exposure to the elements and window cleaning. Before selecting a product, ensure it has a reasonable warranty.

These are some types of bird-safe applications that you may consider in building retrofits or new builds, many of which offer custom designs.

Feather Friendly dots on window

Feather Friendly window markers. Photo: FLAP Canada


Perforated (one-way) window film

Note: avoid transparent or clear products as they will not be effective at reducing bird collisions

Patterned window films

External coverings such as grilles, shutters, exterior shades, or perforated aluminum panels

Unique and attractive architectural design elements can provide the visual cues that birds need to avoid a collision, while enhancing the overall aesthetics of the building. Some measures can also aid in climate and lighting control and increase privacy.

aluminum panels over window

PAC-CLAD | Peterson – Aluminum panels. Photo:

Opaque and frosted glass

Opaque and frosted glass may reduce bird-window collisions if the outside surface of the glass is frosted. However, some glass with a frosted exterior surface can be difficult to keep clean.

  • TIP: For smaller-scale projects, consider some of the methods available for residential use.

Ineffective mitigation measures

These measures have been proven not to be effective at reducing bird-window collisions. Alternative methods should be selected.

  • Interior blinds, drapes, and screens

    Mobile interior treatments are problematic because they do not address reflections on the outside of the window. It is also difficult to ensure they will be used properly and reliably by building occupants.

  • Angled glass

    Although angled glass may reduce bird collision injuries, evidence is lacking to show that it reduces the overall number of collisions. There are also architectural and cost challenges in using this strategy.

  • Awnings and overhangs

    These measures do not eliminate reflections on the outside surface of the window.

  • Tinted or coloured glass

    Coloured or tinted glass can still be reflective.

  • Ineffective bird deterrents

    Measures such as high-pitch frequency devices, scare balloons, noise-makers and cannons, birds of prey recordings, and plastic owls are not effective.

  • Treatments applied to the inside of windows

    Reflections on the outside surface can render them completely invisible, either at all times or at certain times of the day.

  • Any visual markers that are spaced too far apart

    Applying decals that are too widely spaced leaves most of the glass untreated and deadly.

Please note: Although light reduction practices at night can help reduce nighttime bird-window collisions, they will do little if anything to reduce daytime strikes. Therefore, even if you already have responsible lighting practices at your building, it is imperative that you reduce the risk of daytime collisions by treating the glazed surfaces on your building to be bird-safe.