Jul 10 2008

Windows Kill

Published by at 10:01 am under Bird Behavior,Peregrines

When our young peregrine died last month, many people wondered how he could crash into a window without even seeing it.

In fact, windows are the number two human-induced cause of death in birds. According to Dr. Daniel Klem, Jr. of Muhlenberg College, 1 billion birds die every year in the U.S. by hitting windows. That’s 2.7 million birds per day.

Half of the birds who hit windows actually survive the initial impact but can easily be captured by predators while stunned. Those deaths don’t count as window kills, though they’re related.

Why do windows kill?

Take a look at the building pictured here. Even to us it looks like trees and sky. We’re too large to fit through the “fence” (the window frames that hold each pane) but birds think they can fly through it. Sometimes they see their own reflection and believe it’s a safe flyway because another bird is using it. Other times they can see into the room and try to fly inside. At night they’re attracted by lights.

People are fooled by glass too, but it doesn’t kill us. How many of us have bumped into a glass door because we didn’t see it? We survive because we move slowly – and not head first – into the glass.

How can we prevent window kills?

Sadly, a few decals won’t do the trick. The rest of the window is still dangerous.

Reflective glass must be treated on the outside to alter the entire look of the windows. The treatment must make the birds see a wall or a mesh too small to fly through. For buildings like the one pictured here, it means coating or etching the outside of the glass or installing mesh or outdoor blinds. It would even help – but only a little – if they didn’t wash the windows.

For transparent glass, closing the curtains or slanting the blinds is all you need to do. Window screens for keeping bugs out are excellent deterrents though they need to cover all the glass, not just half.

At night turn off the lights or close the drapes, especially in high-rise structures during spring and fall migration. Toronto, Ontario has begun a program to do just that, thanks to the Fatal Light Awareness Program (FLAP).

There are many resources on the web to help your home or business reduce window kills:

  • There’s a handy fact sheet here¬†with lots of resources and solutions that work.
  • Audubon has suggestions for your home.
  • The Fatal Light Awareness Program has worked on this problem for 15 years. They have lots of suggestions including new research on UV coatings that birds can see but we cannot.
  • A brief paper by Dr. Klem, with in-depth information, can be found here.

If you are an architect or designer or you are considering building a new office or home, think about the windows before you buy them! It’s an uphill battle to change a building after it’s built.

(photo from Wikimedia Commons.  Click on the photo to see the original.)


p.s. Hierarchy of threats to birds from FLAP Toronto.

6 responses so far

6 Responses to “Windows Kill”

  1. Kristenon 10 Jul 2008 at 2:07 pm

    I recently wrote to building management at Pitt after watching three robins try to land on the “trees” in the first floor windows in the space of 20 minutes. Fortunately they all seemed to fly off unharmed. (I mentioned Sky’s death in hopes that might spur them to action.) May I send them a link to this entry?

  2. Kate StJon 10 Jul 2008 at 3:05 pm

    Sorry to hear your building has window-collision issues. Feel free to send the link.

  3. Nancy Jon 14 Jul 2008 at 4:44 pm

    I’ve been researching this issue since Sky’s death… it seems like there is nothing that can be done for a commercial building with reflective windows that are already in place that would not be prohibitively expensive and difficult to keep in line with the professional, businesslike image such places want to display. I’ll keep looking, though.

    My workplace has one visual “fly-through” in its main entryway that has a lot of non-reflective glass. I’m going to see what we can do about that, because it does claim a few birds each year — and those are just the ones I see.

  4. Kate St. Johnon 09 Oct 2008 at 9:28 am

    Dr. Klem is still collecting window-kill data. If you find any window killed birds, please report them to Dr. Klem via his web page at http://www.muhlenberg.edu/depts/biology/faculty/klem.html
    From his page, click on the Acopian Center for Ornithology, then Birds and Windows.

  5. Kate St. Johnon 15 Sep 2011 at 9:18 am

    Received this email with a NYTimes link from Lily today (15 Sept 2011):
    Hey Kate,
    In case you haven’t seen this article today: http://www.nytimes.com/2011/09/15/nyregion/making-new-yorks-glass-buildings-safer-for-birds.html?_r=1&hp
    – Lily

  6. Caraon 17 Jul 2012 at 8:26 am

    Windows are deadly for many, many birds and the first thing that needs to happen to help solve this problem is raising awareness. Yes, millions of birds die every year because of striking glass, but people don’t seem to know enough about it! I had the pleasure of working on a project this year which is aimed at testing and developing methods to help provide a solution, and it’s being conducted in our own backyard- just an hour outside of Pittsburgh at the Powdermill Nature Reserve. http://www.carnegiemnh.org/powdermill/tunnel.html

    And we’re finding very interesting things! And I just wanted to share this with everyone, so people do know that there are other options for bird safe windows that are showing to be quite effective. http://www.ornilux.de/cms.asp?Sprache=en

    And here’s one last link, to a page from American Bird Conservation on the subject http://www.abcbirds.org/abcprograms/policy/collisions/glass.html

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