Why glass windows kill birds and how to prevent it

Bird Safe manual

Audubon Minnesota’s Bird Safe Building Guidelines manual is available free online.

Published Aug. 7, 2011, in the Wyoming Tribune Eagle, “Killer kitchen window adds to national bird death toll.”

2014 Update: Check Audubon Minnesota’s website for more information about their Bird Safe program: http://mn.audubon.org/project-birdsafe.

By Barb Gorges

It became an almost daily occurrence this past May: a soft thump on the glass as another visitor to our backyard and bird feeders hit the kitchen window.

I tried putting up big stripes of blue painter’s tape and that helped a little. Mainly, we needed to remember to check the yard for dazed birds before letting our bird dog out. Luckily, the couple we saw her take seemed to be the only window fatalities—that we knew about.

Migration seemed to be over after the first week in June. With just the regulars now, including the house finch with the white head and her friends, there have been no more collisions.

It’s the visiting birds, 25 other species in our yard, mostly during spring migration and not so much in the fall, which get confused by a window that reflects the trees. At least with the feeders within only feet of the window, they didn’t have a lot of momentum when they hit. But it wasn’t always feeder birds, and it wasn’t always that window. In fact, it is windows everywhere.

Audubon Minnesota, a state office of the National Audubon Society, came out with a booklet available online for free, Bird-Safe Building Guidelines, that explains the problem and solutions at the architectural level. Go to www.mn.audubon.org, where there is a link to the 40-page pdf, or put the booklet title in the website’s search window.

People love buildings with lots of natural light. If they are well-insulated, windows can save energy on lighting. But those glass-sided high-rises, and even residential windows, are calculated to kill hundreds of millions of birds per year in the U.S. Spring and fall migration are the most problematic times of year.

Anything that breaks up the glass expanse, like my painter’s tape (engineered to peel off easily), or screening, helps. It has to be applied to the outside surface, though. Waiting to clean the dust off the outside of your windows until after migration might help, too, as can drawing drapes and shades to prevent birds from seeing straight through your house to a window on the other side.

Scaring the birds away with items hanging in front of the window, things that move in the breeze, like flagging, or that move and shine, like old CDs, might do the trick.

At the architectural level, Bird-Safe Building Guidelines discusses ideas for new buildings and retrofitted buildings: netting, fritted glass, films applied to glass, etched glass designs, glass sloping to reflect the ground, taking into account proximity to habitat and feeding sites, and special glass making use of birds’ ability to see ultraviolet patterns we can’t. Problems occur mostly at the ground level and first few stories of buildings.

Then there is the problem of lit up buildings attracting night-flying migrants, especially during bad weather, and all the ill effects of light pollution in general. Turning off interior building lights at night saves money and birds, and so does making sure outdoor lights are not needlessly lighting the sky.

Our killer kitchen window, a six-foot wide replacement with sliding halves, currently is only half screened. The track is still there for the full screen, so we should order one and put it in place from early April to mid-June. All of the glass will be less reflective then and birds still colliding may bounce off the screen.

But next spring, before we let Sally out, we’ll check the area below the window for dazed birds. No need to increase the dog’s “life list.”

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