Birds and windows don’t mix.

Imagine you’re a bird, and you are flying through the clouds, then BAM! You hit something and get knocked out. You saw clouds and sky, but you had no idea it was the reflection of a glass window. Anyone who has ever accidentally walked into a too-clean sliding glass door may also know the feeling to some degree. You might feel just a little embarrassed if you walk into a glass door, but for birds, the consequences of colliding with glass are much more severe. They often get seriously hurt or die from window collisions.

Along with cat attacks, window strikes are one of the top reasons birds are admitted to wildlife rehab centers like PMWC. According to the non-profit FLAP (Fatal Light Awareness Project), between 100 million and 1 billion birds are killed by impact with glass every year. Birds who hit windows break wings and other bones, have air sac injuries, but mostly suffer from head trauma. There are many reasons birds fly into windows. Sometimes birds just see the clouds reflected in the windows, and do not understand that the glass is not an extension of their natural world. That makes sense, because they see reflections of clouds, sky and trees. Homeowners, sitting in their houses, often hear a dull “thud” and come outside to find a fallen bird who hit their window.

And birds who migrate, particularly at night, hit skyscrapers or are confused by nighttime lights, causing them to crash. For some birds, like the American Woodcock and many warblers, their migratory path is right over center city Philadelphia. If they hit a window, they fall and end up on the street in the city – an utterly bewildering, frightening experience for a deep woodland bird who knows nothing of the city, (unlike our ubiquitous house sparrows). Every year we get dozens of calls about fallen window-strike woodcocks and warblers in center city, during both spring and fall migration. And fall migration is starting to happen right now!

What can we do to help these birds who mistake our human made glass for their natural flight path? The answers are divided into two categories: preventing bird window strikes, and helping birds who have already hit a window.

If you have found a bird on your property who has hit your window, look him over for injuries like blood, asymmetrical wings, etc. If the bird has injuries, call PMWC right away. If the bird does not have obvious injuries, but will not fly away, place him into a closed cardboard box and put the box in a quiet place. Wait one hour. Then, open the box outside. If the bird flies away, great! She was only stunned. But if the bird will not fly away after a rest period in a box, please call and bring him to PMWC. The bird will be checked and treated for broken bones and head trauma. We have successfully treated many of these birds. If you have found a window strike bird in center city Philadelphia call us immediately.

To prevent birds hitting your windows in the first place, many products are on the market that allow birds to understand that windows are not the sky. Translucent bird strike stickers are a great choice for homeowners. The stickers are available in various configurations, look like pieces frosted glass, and are attractive. See the American bird conservancy window strike page. For companies or large, industrial sized windows, we recommend the solutions at

As always, if you have questions about any wild animal or bird, and how to help them, please call us at 267.416.WILD (9453) and we will be happy to find a solution to most wildlife issues.

About PMWC

Philadelphia Metro Wildlife Center is a non-profit, wildlife rehabilitation organization serving Philadelphia, Montgomery, Chester and Delaware counties. They are now located in their new permanent home at 2815 Township Line Road, Norristown. For more information visit their website at


About Michele Wellard 2 Articles
Michele is an Assistant Director at the Philadelphia Metro Wildlife Center.

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