One winter day a couple years back, I came home from work to find my kitchen floor strewn with glass. A jagged hole gaped in the window and a sharp-shinned hawk lay dead on the floor. Most likely the hawk was chasing one of my smaller feeder visitors when the window got in its way.
Bird-window crashes are unfortunately common. Mine was an extreme case; usually collisions involve small birds, such as finches, that fail to break the glass and fall unnoticed to the ground. Sometimes the birds are merely stunned and recover in a few moments. Often, however, they die. The number of window-killed dead are not trivial: realistic estimates range as high as 100 million per year.
Does this mean that you should stop feeding birds? Not at all. It means that if you notice birds bouncing off your windows, you should take steps to eliminate the problem.
Some SolutionsYou can start by simply moving your feeders to new locations. Usually bird strikes occur at just one or a few windows, and moving feeders away from them may solve the problem entirely. You can also try placing your feeders very close to the glass if a feeder is just a foot or two away from a window, panicked birds may fly into it, but they won't have enough momentum to hurt themselves.
If you don't want to move your feeders, or if relocating them doesn't solve your problem, you'll need to alter the appearance of the offending window.
First, you need to determine exactly why collisions are occurring. Are birds confused because the window is reflecting the landscape behind, or because it's so transparent they think it isn't there?
Transparent WindowsTo find out, you'll need to take a bird's eye view. Go out to your feeder and look at the window. Can you see through it? If so, the birds can too. Is something inside the house attractive to birds, such as a plant? Try moving it. Is another transparent window located on the opposite side of the house? If it is, birds may envision a passageway through your living room. Try making the windows less transparent by changing the lighting inside the house pull a shade, or open or close a door.
You can also render the window less transparent by taping paper or cardboard to the inside of the panes. One week last summer, dozens of gold finches began flying into my office window. I quickly taped sheets of paper onto the glass and ended the problem entirely. Of course, the paper was unsightly; I later replaced it with strips of cardboard. Commercially available hawk silhouettes will also work, as long as you use several they work not because they look like hawks, but because they break up the window's appearance. Note! Do not attach objects directly to thermopane windows without consulting the manufacturer.
Reflective WindowsWindows that mirror the outside habitat present a different problem. If you see branches or sky reflected in the glass when you look at your window, you'll understand why the birds are confused. In this situation, changing the lighting inside the house or fastening objects to the inside of the glass won't help, because light is not passing through the window.
Instead, you'll need to alter the window's appearance by placing something on the outside. As a temporary measure you can paint the window with soap or wax, which can be removed easily. Then try strips of paper or cardboard. Or hang ribbons, colored string, or even mobiles. The objects may look strange but they'll prevent needless deaths.
Another solution is to place a screen such as a garden-protection netting over the window. This won't obstruct the view in fact, birds will continue to fly into the window. However, they should bounce off the netting unharmed. One member of the Cornell Lab of Ornithology used this technique to end an average mortality rate of seven birds each day! Netting can be mounted on a frame for easy installation and removal.
Dazed BirdsBirds don't always die when they strike windows. Sometimes they fly away apparently unharmed, other times they fall to the ground stunned. If you find a dazed bird, take it inside where predators can't reach it, and place it in a dark container such as a shoe box. The darkness will keep it quiet when it revives. Release it as soon as it appears awake and alert.
If you don't see birds striking your windows, you probably don't have a problem. On the other hand, you may have a problem without realizing it. Please check the ground below your windows periodically, especially windows with feeders nearby. If you find dead birds, move your feeders or modify the windows. Birds face plenty of natural dangers let's not subject them to unnatural ones.
Reprinted with permission. Copyright Cornell Lab of Ornithology. Bird Bulletin Number 10 Cat. No. 220. September 1992