A worker installs bird-window collision mitigation – white adhesive dots – on the windows at the main entrance to Assiniboine Park Zoo.
Urban green spaces can be important refuges for native plants and animals. At Assiniboine Park, keen naturalists have documented more than 160 bird species visiting or nesting here! As part of our involvement in the North American Songbird SAFE (Saving Animals From Extinction), we are committed to protecting native birds that call Assiniboine Park home. Read on to learn how we create a bird-safe environment at the Park and how you can help at your home.
Have you heard a “thump” against a window, or found a stunned bird sitting dazed beneath the glass? Window collisions are one of the top sources of human-caused bird mortality, killing millions of birds every year. During the day, birds collide with windows because they interpret the trees and sky reflected in the window glass as real, or they may think there is no barrier and attempt to fly through to what appears to be open space. Colliding with a window frequently results in the bird’s death, even if the bird only appears stunned or manages to fly away. Most of these collisions occur during their annual migrations in spring and fall, when billions of birds navigate unfamiliar territory.
Figure 2. Left – A window mitigated with chalk marker designs. Right – The mitigated retaining wall at the Bison Snack Shack.
Since 2013, we have been identifying high-risk windows across the Park and Zoo and mitigating them by applying treatments to reduce the number of bird injuries and deaths. The white dot patterns on windows, such as at the Bison Snack Shack and the Polar Bear habitat, help make the glass more visible to birds (Figure 2). Last year, we applied window treatment to more than 350 m2 of glass at the Zoo’s main entrance (Figure 1), a project funded partly by the Nature Manitoba Salzmann Songbird Grant. These installations have helped save countless birds at Assiniboine Park.
Nearly half of bird-window collisions occur at low-rise buildings, like individual residences, so we can all help keep birds safe by treating the windows at our homes. To deter birds from colliding with windows, birds must be able to interpret the glass as a solid object that they need to avoid. One of the easiest, non-permanent solutions is to draw lines, dots or other patterns using chalk markers or soap (Figure 2). Decals and other stickers can also be effective, but keep in mind the following:
- Gaps between the dots, patterns, or decals must be no more than 5 cm. If the dots are more than 5 cm apart, small birds like kinglets and warblers may still try to fly through the gap.
- The treatment must be applied to the outside of the window to break up the reflection of trees and sky visually.
Window treatments can reduce bird collisions by 60-95%, so mitigating your windows at home is a simple action with a big impact! For more ways to prevent bird-window collisions, check out the American Bird Conservancy website.
