Join the Flock: Protecting Migratory Birds from Window Collisions

Posted October 8, 2018

Guest blogger: Hannah Mason, Special Projects Volunteer

Any time you want to see birds from around the globe, you can visit the Wings of the World at the Cincinnati Zoo. But during spring and fall migration seasons–like we’re in right now–you can see bird travelers flying right through your backyard, on their way south to Central and South America. In fact, Cincinnati sits right on the western rim of the Atlantic flyway for land and water birds migrating from Canada and Greenland. Tens of thousands of birds are estimated to migrate through our area every year.

Birds in flight (Photo: Reva G)
Birds in flight (Photo: Reva G)

Unfortunately, not all of them make it to their sunny southern vacation grounds for the winter. Glass windows are the second leading cause of bird death (after house cats). Between 400 million and 1 billion birds are estimated to die by window collision each year in the U.S. alone. That’s approximately two birds per house per year, which doesn’t seem like a lot… until you think about how many houses there are in the United States.

This is a problem everywhere there are windows. Here at the Zoo, we want to do our part to prevent bird collisions. We’ve been noticing and logging bird collisions for years, but this spring we stepped it up and launched a full-fledged monitoring program, thanks to superstars like our weekly volunteers and aviculture staff.

“The goal with the program is to reduce our impact as much as possible,” says Kim Klosterman, aviculture keeper at the Zoo. “We want to set an example for our visitors and show how you can help us solve this problem. If we can set an example of a bird-friendly environment for our visitors, and they see what we’re doing and that it’s easy for them to do, too, then we’ve achieved our goal.”

This monitoring program has helped us find the biggest trouble spots in the Zoo–where we have the most bird collisions–so we can focus on these places first.

Prevent Bird Collisions with Us

The bottom line: birds fly into windows because they can’t see them. So, the solution? Make the windows more visible! There are various ways to do this, and many of them you can do at home, too–and they can even be fun and get the family involved.

Applying dot decals to the Free Flight Aviary window (Photo: Shasta Bray)
Applying dot decals to the Free Flight Aviary window (Photo: Shasta Bray)

We’ve been trying out some ways to bird-proof the most highly frequented windows at the Zoo. For example, our Free Flight Aviary windows are made of custom, double-paned glass that reflects UV light. If you look really close, you’ll see there is a faint, spider-web-like pattern in between the glass panels. We can hardly see it in the glass, but birds can see UV light reflecting off of this pattern and know to stay away!

We are also beginning to use special dot decals on some windows to make them more visible to birds. The dots break the reflective surface into smaller sections that birds won’t try to fly through. We have examples from several brands on our Zoo windows that we’ve tried out for you, and you can buy them for your home, too:

  • CollidEscape sells high-performance tape and dot-shaped decals that you stick right on your window.
  • The American Bird Conservancy recommends its own ABC Bird Tape, sold through CollidEscape, which can be placed on windows in vertical stripes.
  • Feather Friendly sells even smaller dot-shaped decals for windows.

Each strip of tape or dot decals should be placed no more than 4 inches from each other to be effective, and as close as 2 inches apart for maximum prevention.

There are other ways to make your windows more bird-friendly, too:

  • Leave your blinds half open to prevent bird collisions (Photo: Shasta Bray)
    Leave your blinds half open to prevent bird collisions (Photo: Shasta Bray)

    A fun, easy way to make your windows more visible is to paint them! You and your family can practice your art skills with seasonal or bird-themed paintings while making your home safer for your feathered neighbors.

  • Installing mesh screens on the outside of your windows can also prevent birds from colliding with the glass–they’ll bounce off of the mesh with much less risk of injury.
  • And a simple thing to do if you have blinds or curtains: leave them half-closed. It’s not as effective as the decals or bird tape, but anything you can do to leave a pattern on your windows helps birds notice your window and stay away.

Go Lights Out

Most birds migrate at dawn or dusk, but a significant amount of them also fly through the area at night. Night-flying birds use the stars to navigate by, so they sometimes get confused by the lights on in buildings and windows at night and end up flying into them. The best way to prevent bird collisions during the nighttime is to keep your lights off between midnight and dawn during migration seasons!

Everyone can do this at home, and the city of Cincinnati itself is stepping up to take this to a different level. The Lights Out project was started by the National Audubon Society as an initiative to get residents and city officials to turn off exterior lights in cities around the U.S. There are 26 local chapters right now, and Lights Out Cincinnati is one of them, thanks to dedicated partners at the Cincinnati Zoo, Cincinnati Nature Center, and Cincinnati Museum Center.


Here at the Zoo, we’re all about protecting animal species around the world, and preventing bird collisions during migration season is one of the simplest and most important ways we can all pitch in to help protect our local birds.

“Birds are important indicator species for the health of the local environment,” says Klosterman. “Birds aren’t always beloved in people’s minds, but one of our goals is to help everyone see how important they are and to improve mindsets about birds.”

Thanks for helping to prevent bird collisions alongside us! If you do come across a wounded bird at your home, here are a few places you can call:

  • Scarlet tanager (Photo: Ryan A Candee)
    Scarlet tanager (Photo: Ryan A Candee)

    Second Chance Wildlife Rescue Association is dedicated to Ohio wildlife conservation. Call their helpline at 513-875-3433 to speak to a wildlife rehabilitator.

  • Raptor Inc. is dedicated to rescuing predatory birds (like eagles, hawks, and owls) in the Cincinnati area. If you see an injured raptor, call one of their dispatchers at 513-825-3325.

Thanks to the National Audubon Society, National Geographic, BirdLife International, and Cornell Lab of Ornithology, 2018 has been named the Year of the Bird. It’s in honor of the 100th anniversary of the Migratory Bird Treaty Act which protects migrating birds in the U.S. So it’s a perfect time to flock together to conserve local birds right here in Cincinnati! We’ll be monitoring bird collisions and bird-proofing windows right along with you.