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Glass is death to birds

May 19, 2005

In discussions of energy policy I find that radical environmentalists have done their work well; never have I mentioned windmills without someone saying, “But don’t they kill birds?”

The answer, unfortunately, is “yes.”  Early windmills (a notorious example in California comes to mind) were relatively small, turned fairly fast, and killed a basket-full of birds a week.  Even worse in my mind, they were unprofitable.  Not so the new windmills.  They make a tidy profit.  (Before you go hopping around on one foot yelling “subsidies!” remember what it takes to keep access to Middle Eastern oil.  And the climatic penalties of carbon-based fuels are dispersed among all humanity, with the poor most vulnerable.)

Also depressing, the answer to the “question not asked” is that all man-made structures kill birds, and glass-covered buildings are the worst offenders.  Birds are dumb, and have not adjusted to tall mirrors in their path.  Just this morning I encountered the grisly evidence as I arrived at work: a bird of some kind, lying in front of the entrance with compound fractures of the neck and skull.  It must have hit the windows at high speed.  I tossed it into a trash can and went inside to wash my hands.

(That picture is below the “Read More” link, because, while the bird had been beautiful, the picture is not.)

But buildings can be optimized to reduce the impact on birds, and current windmills (because of their enormous size) turn so slowly they kill very few birds – on the order of one or two a year per tower.  Even this number may be inflated; last week I found a dead bird under a tree without a scratch on it.  Did the tree kill it?

Some improvement in buildings can be had by angling the windows slightly inward at the base, so they reflect the ground.  But the effect isn’t very attractive, and anyway it isn’t practical to retrofit existing buildings.  Could there be other ways to prevent bird collisions?  Birds hear pretty well.  I wonder if it would be possible to emplace ultrasonic barriers on buildings that would make them turn away?  Or an active system using some of the new “directed sound” technology that is just coming to market?  That would be a neat research project to undertake.

  1. May 20, 2005 at 18:52 | #1

    The windows throughout the university where I’m at have been hit by birds so many times they’re covered with the imprints left by the impacts.  It’s kind of disturbing when you figure out what you’re looking at.

  2. May 20, 2005 at 19:05 | #2

    Eeeeww!  Birdsplats!
    In the first picture you can see where this bird hit the window in the bottom pane on the right-hand side.  Then there were small feathers on the door handle of the building and a couple on the sidewalk around the bird.  Apparently it flopped around a bit before expiring.

    It was such a pretty thing, not your average sparrow or starling.  I wonder what kind it is?

  3. May 22, 2005 at 17:10 | #3

    It’s a Yellow-billed Cuckoo.

  4. OB
    May 26, 2005 at 07:47 | #4

    I work in a high-rise, and every now and then there are pigeon parts littering the premises, compliments of the hawks that nest on the roofs of our building and the others in the vicinity.

    Ah, life in the food chain!

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