Fact Sheet

Click here to download a PDF of the Acopian BirdSavers Fact Sheet.

When people think of bird mortality they usually think of cats, wind turbines, and pesticide poisoning, among other causes. In fact, in North America the largest number of birds are killed each year by glass! Windows in our homes and other buildings can be deadly to birds. Many people do not realize that birds are killed at the windows they look through unless they happen to be there when the bird hits the window. Birds that die directly under the offending window are often taken by scavengers – cats, raccoons, skunks, chipmunks, other birds, etc. If it is a window where many birds die from collisions, even though you do not realize that birds are dying there, scavengers know and routinely check the area for fresh food. Many times, the bird that just hit the window dies immediately. Other times, the bird may fly away only to die later. Sometimes birds recover if the strike is not too severe.

Although the “incidental, accidental, or unintentional take” of migratory birds is a criminal violation of the Migratory Bird Treaty Act, the U.S. Fish and Wildlife Service does not arrest anyone when birds are killed at windows! This is a good thing, as windows kill lots of birds. Because this problem is so overwhelming and there are no easy solutions, the USFWS doesn’t even attempt to deal with the problem!

Until glass manufacturers design and manufacture window glass that deters birds from flying into it, and until people begin to use it, there appears to be little we can do to effectively eliminate the problem. One window manufacturer in the USA has recently developed a clear film that can be applied to existing windows that does reduce the likelihood of birds colliding with them. The film works remarkably well, but the manufacturer has not yet decided to market this product.

In lieu of the glass manufacturers’ future solutions, Acopian BirdSavers can significantly decrease or eliminate the incidence of birds killed at your windows. A vast majority of people who have Acopian BirdSavers on their windows or have seen Acopian BirdSavers on windows, if they even notice them, admire their aesthetic appearance and are happy to be killing few, if any, birds. If you like, you can even make your own Acopian BirdSavers!

How to make Acopian BirdSavers
Acopian BirdSavers need to be installed on the outside of the window. This is so that birds flying towards the window will see the cords, avoid them, and therefore not fly into the glass. Acopian BirdSavers consist of 1/8 inch diameter ‘paracord’ hanging approximately four inches apart. The ‘paracord’ we use for Acopian BirdSavers is dark olive green color. Paracord is available at many hardware stores and online. The word ‘paracord’ is an abbreviation for ‘parachute cord’ and is the nylon cord used in the suspension lines of parachutes. A fun fact is that Acopian BirdSavers uses paracord that is made by the same company that made the paracord under the parachute that landed the Curiosity rover on planet Mars in 2012. And that company, CSR Inc, is based right here in Pennsylvania.

We have been using dark olive green colored parachute cord for many years and it has proven very effective. The results of scientific tests conducted by Dr. Daniel Klem, Jr. confirm our own conclusions that Acopian BirdSavers with dark olive green colored parachute cord are very effective in preventing bird-window collisions. We are fairly certain though, that any dark color, or for that matter probably any color or any type of cord, will be just as effective as the dark olive green color paracord. Any method you use to hang cord in front of a window will significantly decrease the number of birds that are hitting a problem window.

We space the Acopian BirdSavers paracords four and one quarter inches (4-1/4˝) apart, which is a very good balance between the visual aesthetics of the paracords on the window and the protection of the birds. Many people think Acopian BirdSavers look so cool that we’ve given them the alias name of “Zen Wind Curtains”. One recent college graduate told us that she can’t wait to own a house so she can put “Zen Wind Curtains” on the windows because they have such a calming effect on her! Because some people worry about the possibility of smaller birds trying to fly between the cords, although this very rarely happens, the paracords can be spaced closer together than 4-1/4” if you prefer. Experience has shown that BirdSavers with cords spaced at 4-1/4˝ stop even small hummingbirds from colliding with glass. Equally surprising is that birds sometimes fly into solid objects with no windows (see FAQ – Why do BirdSavers prevent birds from flying into windows?)

The bottoms of the cords don’t need to go all the way to the bottom of the glass; it looks more aesthetically pleasing when you can see an inch or two of space between the bottoms of the cords and the bottom of the glass. In other words, they look cool!