Conservation Corner: Window Collisions

By Gael Bissell

There it is…that awful womp!..the sound of a bird hitting one of your windows! You run outside and hope there isn’t a dead or clearly wounded bird on the ground. Whew… no bird. All good, right? Not really. National Audubon reports that 50% of bird-window collisions are not detected and many of these birds will still die within a few days through trauma. Studies show that over 1 billion birds are killed annually through window collisions that increase during both the spring and fall bird migrations. Birds simply cannot detect glass, and they often fly right into those wonderful reflections of the sky or nearby vegetation. About 44% of bird-glass collisions are in one to three story residences, 56% in low rise buildings (i.e. four to 11 stories), and less than 1% crash into buildings 12 stories or higher. 

Flathead Audubon monitored a number of Kalispell buildings with large windows once a week for several weeks during the 2022 spring migration. We found only one dead bird, a juvenile American Redstart that had hit a car dealership window, which was pretty good news. On the other hand, Flathead Audubon volunteers who also monitored bird collisions at their own residences for over a year reported many dead birds, particularly if mitigation such as strings or dots were not used. There is something we can do, and it is all spelled out in this awesome new brochure from National Audubon.

For example:

  1. Move your feeders closer to your windows (1-3 ft.) so your feathered friends don’t have speed before heading into a window.
  2. Fix your windows through a wide variety of store and DIY solutions (hanging cords, use exterior window screens, or place small dot film on your window).
  3. Limit nighttime lighting which can draw in and disorient birds.

The Chicago McCormick Place, a 2.6-million-square-foot glass building and convention center on the shores of Lake Michigan, has been responsible periodically for killing thousands of migrating songbirds (All About Birds, April 2024). The convention center finally just installed bird-friendly windows on every level. The city also recently adopted building codes for bird-friendly windows. You can see two window treatments up at Lone Pine State Park and pick up this new National Audubon brochure at our next Flathead Audubon meeting!  If we all do a little to reduce collisions and nighttime lighting, we can make a big difference in reducing bird mortality. Thanks!