Reducing bird window strike – take these steps to assess your site

Bird strike is one of the highest causes of bird mortality globally and the rapid increase of urbanisation continues to exacerbate the damage caused by our buildings and other man-made infrastructure. Our homes, our places of work, where we study and where we relax all have a unique set of factors that put all species of birds at risk of window collisions.

The most common cause of bird-window strike on buildings is the reflectivity and transparency of commercial and residential windows. The reflection of vegetation and the sky creates the impression of an available flight path, but in reality, results in the bird colliding with the glass. Transparent windows are essentially invisible to birds, especially when there is a line of sight through to the other side. If birds can see vegetation or sky reflected in a window, the risk of impact with it increases.

Building design can also play a significant role in window strike. Large, continuous areas of glass that are even slightly reflective are 17 times more likely to cause collisions. Landscaping features can also increase the risk of window strike. Landscaped green areas or remnant patches of vegetation as close as 100m to a building, can increase the risk of window strike. These areas provide habitat and refuge for birds but also bring them closer to the threat. Garden features such as bird-feeders also increase the rate of bird-window collisions, especially when over half a metre away from windows.

What can we do to reduce the risk of bird-window strike?

To help address the problem, steps can be taken to mitigate or at the very least, adapt our surroundings. You can begin to assess your homes and the surrounding environment to determine whether you are able to introduce any deterrents.

Assess your site and ask yourself:

  1. Are your windows transparent or highly reflective?

If yes – consider placing small decals, 10cm apart across the entire window. The space between decals is the most important factor, not the pattern or picture. If you would rather not place visible patterns on your window, then UV markings can be applied. Different types of UV markings should be used as the type of UV light that birds can see varies between species. Other measures may include using vertical blinds to ‘break up’ the window surface area; leaving window screens closed and clearing as much vegetation as possible from around windows, including moving inside plants away from windows.

  1. Do you have a bird feeder further than half a metre from your windows?

If yes – consider moving the feeder within half a metre of the window as this will stop birds reaching a high flight velocity which, can cause severe trauma or death when colliding with windows.

Other resources

The Fatal Light Awareness Program (FLAP) based in Toronto, Canada, is an initiative dedicated to the management and prevention of bird-window collisions. Dr. Daniel Klem, Jr., Professor of Ornithology and Conservation Biology at Muhlenberg College in Pennsylvania has developed a short, home and business self-assessment quiz to help determine whether a certain building is a risk https://birdsafe.ca/. The American Bird Conservancy has an extensive list of ‘ABC bird-friendly' certified products that have been field tested and found to help reduce the number of window collisions https://abcbirds.org/get-involved/bird-smart-glass/. You can also report any bird window/car strikes using our online survey at https://www.surveymonkey.com/r/aussiebirdstrike.

Next steps for the Australian Bird Strike Project

Please continue to submit your bird window and car strikes using the link above. We are currently compiling data sources to determine the scale of the problem in Australia and will publish our results online next year. Now that you’ve tried to mitigate the threats at your site, look out for further solutions in future posts.


Post written by Kat Aburrow, BirdLife Australia Volunteer - Bird Strike Project

Contact us at birdstrike[AT]birdlife.org.au

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