Building Bird-Safe Cities

Up to 1 billion birds die each year from window collisions in the United States. Birds can’t tell the difference between trees or sky reflected in glass and the real landscape outside, so they often collide with windows under the illusion that they have free space to fly. Birds are also drawn to illuminated windows at night, which can result in massive collision events during spring and fall migration periods when many birds migrate after dark.

Birds are critical to the health of our ecosystems, so it is important to protect them. Window collisions are one of the leading bird killers, second only to predation by cats. Luckily, there are a variety of solutions to help reduce building collisions, some of which are relatively cheap and easy to implement. Groups in Pennsylvania like Bird Safe Pittsburgh, Bird Safe Philly, and the Carnegie Museum of Natural History are conducting research and advocating for changes that will reduce collisions. Pittsburgh and Philadelphia also participate in the Urban Bird Treaty, a U.S. Fish and Wildlife Service program to conserve urban bird habitat and reduce hazards to birds.

Up to 1 billion birds die each year from window collisions in the United States.

Lights out for Birds

Many major cities across the country have implemented “Lights Out” programs during peak migration times to reduce nighttime collision events. Both Pittsburgh and Philly have Lights Out programs, where commercial and residential buildings commit to turn off their lights between midnight and 6 a.m. during migration season. Many major buildings in each city have committed to participate in the Lights Out program, including the Comcast Technology Center and Comcast Center in Philly and the BNY Mellon Center in Pittsburgh. Building owners can also reap benefits from participating in the program, like reduced energy bills from lower electricity usage.

Bird-Safe Glass
Flight tunnel. Image credit: Powdermill Nature Reserve

Powdermill Nature Reserve in Westmoreland County conducts research in partnership with the American Bird Conservancy on how birds perceive glass. A small number of birds captured through Powermill’s banding program are used to test the effectiveness of different bird-safe window treatments. Birds are placed in a tunnel and allowed to fly towards an apparent opening beyond panes of glass fitted with the treatments. The bird is captured before it collides with any of the panes, but the experiments help determine which treatments are effective enough for the bird to avoid, and which still uphold the illusion of an open flight space.CreatCAdding bird-safe glass to buildings doesn’t have to be an eyesore. Projects at the Carnegie Museum of Natural History and the University of Pennsylvania show how the addition of bird-safe glass can make urban spaces safer for birds without compromising appearance.

On Your Property

Spring is still weeks away, but that means now is the perfect time to start preparing for the migratory season. Homeowners can play a big role in keeping birds safe – according to research from the U.S. Fish and Wildlife Service, 44% of bird collisions occur at residences. Here are some ways you can help protect birds passing through (and living in) your neighborhood:

  • Apply tempera paint, decals, or other treatments to the outside of your windows. A closely spaced grid of dots is effective, or you can get more creative and paint an attractive pattern.
  • Keep blinds, curtains, or shutters closed during the day.
  • Install screens on the outside of your windows.
  • Turn indoor lights off at night, especially during the spring and fall.
  • Report fatal window strikes to help support ongoing research. Organizations rely on citizen science to record window strikes in urban areas. Collecting evidence of where fatal strikes occur, and whether certain buildings are having a disproportionate impact on bird populations, can help researchers advocate for improvements that will make buildings safer.
    • Report a window strike in the Pittsburgh area here.
    • Report a window strike in the Philadelphia area here.
    • Report a window strike anywhere else using iNaturalist or dbird.