If our eyes are windows to our soul, then our windows can be our eyes to soul-enriching birds, at least while we’re indoors. So it is achingly ironic that so many birds collide with windows. Daniel Klem Jr. has spent his career as a professor at Muhlenberg College researching window collisions. He painstakingly established, step by step, that birds don’t see glass; that the head injuries they sustain in collisions kill some outright and many others later; that predators capitalize on stunned birds, increasing window-collision mortality; and that the number of birds killed at windows is astonishingly high — on the order of a billion dead birds every year in the United States alone. If you think his findings are grim, you should know that he has also studied ways of making windows safer for birds. He works with glass and window manufacturers, trying to develop glass that is more visible to birds, and he has done experiments to help us prevent collisions with the windows we already have.
One of his discoveries is especially important for those of us with bird feeders. Klem learned that birds are killed most frequently at windows 15 to 30 feet from a feeder, that birds can build up enough momentum to kill themselves if they leave a perch as close as 3 feet from a window, and that kills drop to virtually zero when feeders are less than 3 feet away.
My hunch is that birds may be more likely to see the glass at that close distance. Klem believes that, if they do take off in a hurry, they won’t be going fast enough to injure themselves seriously if they hit the glass.
This is great news. By placing our feeders right on or beside our windows, not only do we get the best possible views of birds, but we get to protect them, too. Feeding stations too large to place directly on or right next to windows should be placed at least 30 feet away. This is especially important for windows showing a clear path to trees or houseplants, windows that reflect trees or sky, and windows with a track record of collisions.
Several kinds of feeders, including small acrylic dishes, suet feeders, and hummingbird tube feeders, can be affixed to windows via suction cups. I have good luck keeping these feeders stuck to the glass by mounting them on squeaky-clean glass after rubbing my finger on the suction cup many times, warming it and transferring oils from my finger onto it. Suction-cup feeders can support birds as heavy as Pileated Woodpeckers.
I also have two larger tray feeders, purchased from a bird-feeding store, with suction cups and a cushioned brace holding them against the glass. They stayed up surprisingly well until gray squirrels started dropping down from the roof onto them.
We’ve also screwed tray feeders into the window frame and suspended feeders from the eaves. My collection has given me wonderfully close looks at birds, and I’ve not had a window fatality since I read Daniel Klem’s research and moved the feeders to the windows years ago. – Laura Erickson
Laura Erickson’s column “Attracting Birds” appears in every issue of BirdWatching magazine. This article appeared in the August 2013 issue. Laura is a co-author of National Geographic Pocket Guide to Birds of North America and the author of Laura’s Birding Blog.