A Canadian study that zeros in on bird-window collisions in a residential context finds that the chances of migratory birds careening into your home are increased if there's a bird feeder placed in the yard.

Now that you’ve been alerted to the fact that your kitty is probably a ruthless, cold-blooded bird murderer that belongs in Birds Anonymous — or maybe not — here’s some more troubling but not all that surprising news: your backyard birdhouse or feeder may be doing your feathered friends a lot more harm than good.

Erin Bayne, a wildlife ecologist at the University of Alberta, recently released the results of his comprehensive study of bird-window collisions — in terms of avian mortality rates, windows/buildings are a much more significant threat to birds than cats — in a residential context. While much attention has been placed on the impact that large, commercial structures such as skyscrapers have on disoriented migrating birds, Bayne's study specifically zeros in on bird-window collisions that occur outside of homes across the Edmonton area.

For the study, published this month in the journal Wildlife Research, 1,458 people — citizen scientists, if you will — were polled online. Thirty-nine percent of them responded that one or more bird-window collisions had occurred at their homes the previous year.

The mean number of reported collisions was between 1.7 and 4.6 birds per home per year with 38 of those collisions resulting in death. Homes in rural areas experienced higher numbers of bird collisions than homes in more urban areas as did homes in older neighborhoods than homes in newer neighborhoods (blame those beautiful old trees).

Bayne explains to The Atlantic Cities: “If you multiple simply the numbers of residential structures that exist in North America by these collision rates — even though they’re low, and they’re still really low compared to some of the big high-rise buildings in major urban centers — it might even be one bird a year, or half a bird per year. But there are so many houses, that adds up pretty darn quick.”

And for those birdhouses or bird feeders? The study suggests that placing one in your yard roughly doubles the chance that a bird might careen into your home especially if you're living is in a rural area. “Putting up a bird feeder is kind of a catch-22 in a way,” Bayne says. Translation: You’re providing a wonderful service for migrating birds — sustenance and shelter — but you’re also putting them in harms way by drawing them closer to into a window-filled danger zone.

Obviously, strategic bird feeder placement is key here and the Audubon Society has a few tips on how lure birds to your backyard with tempting snacks without also luring them to their deaths. Audubon recommends placing feeders within three feet of windows, if possible.

Have you placed a bird feeder in your backyard and subsequently noticed an uptick in dead and/or injured birds on your property? How frequently do you observe bird-window collisions at your home, if at all?

Mother Nature Network