Bird Strikes on Windows

The dangerous relationships between birds and windows is one that comes in varying degrees. Sometimes it's just a quick peck of bird meeting glass. Others it's a small series of crashes and a flutter of wings. The worst, however, are the jarring impacts that resonate throughout an entire house, leaving you and your family members startled and often crippling or killing the bird.

Sadly, these impacts are far more common than you might think. In an article for Audubon magazine, David Malakoff cited that in North America, window strikes kill between 100 million and 1 billion birds annually. According to an NPR story, Professor Daniel Klem of Mulhenberg College things that Malakoff's estimate is too conservative, and that the real number easily exceeds 1 billion birds in the United States alone.

Why do window strikes happen?

It's hard to know for certain exactly why window strikes happen, but observation has granted some measure of insight. The first, and seemingly most common, rationale is that birds simply cannot see glass. The transparency of the glass makes the window look open, and this is often complicated further by a window on the opposite side of the house. This causes what is commonly referred to as the "tunnel effect," meaning that the bird believes that the two windows lack glass and thus represent a clear tunnel to fly through.

The other primary reason for bird strikes seems to be reflections. Windows in houses and buildings can easily reflect the environments around them. So, while the house or building certainly appears to be a house or building, the windows look more like wooded areas which are perfectly safe for flying.

Ways to prevent window strikes

There are a range of possibilities for preventing window strikes. The most effective method is to remove a window, or to completely cover it with something opaque and non-reflective like wood or cardboard. Granted, this removing a window is a bit drastic and not practical for the vast majority of home owners. Thankfully, with a little understanding as to why birds strike windows, home owners can reduce bird strikes with more people-friendly methods.

Covering Windows

While boarding up windows is an extreme solution, it does prove a point. Putting something between the window's glass and the outside world can both alert a bird to a physical object and prevent reflection. The line for most home owners seems to be when such a covering moves from the area of protecting birds and into the realm of obstructing views. Home owners have several options like summer storm screens, to heavier plastic "shade cloth" and even the commercial CollidEscape film, all of which help to remove transparency and restrict reflection to various extents.

Silhouettes and Obstacles

Another tactic is to prevent the bird from coming near the window. Some homeowners put blockades, such as a tree or bird feeder, in front of a window, particularly windows that are struck with some frequency. If you notice that your bird feeder is causing birds to strike your window, then moving the feeder further from your house would be a prudent move. Another popular method, which works to varying degrees, is to intimidate birds away by way of statues and silhouettes. A statue of an owl, or a cut out made to resemble a flying hawk can cause an errant bird on a collision course with a window to change course.