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September 19, 2015 / Leslie

Weekend Birding: Migration-Friendly Buildings and Windows

Migration Has Begun

Millions of North American birds have begun their journey south for the winter. One of the many dangers these birds face is crashing into windows. For thousands of years they have flown along the same path, generation after generation, many of them doing so by instinct, and now there are buildings where there was once trees and sky.

Chicago Bird Collision Monitors

Last week my bird club meeting included a presentation from the Chicago Bird Collision Monitors, a volunteer group dedicated to the protection of migratory birds through rescue, advocacy and outreach. They also work to promote bird-safe lighting and building design to reduce bird collision hazards.

During spring and fall migration, teams of volunteers recover birds that have stuck buildings. Injured birds are taken to Willowbrook Wildlife, the rehabilitation facility near my home, for treatment and release.

White-throated Sparrow – number one on the list


CBCM has recovered over 170 species of birds in the one square mile of downtown Chicago. Some of the most common victims are the White-throated Sparrow, Brown Creeper, Ovenbird, Hermit Thrush, Dark-eyed Junco, Tennessee Warbler, Swainson’s Thrush, Nashville Warbler, American Woodcock, Golden-crowned Kinglet. Sadly, two-thirds of the birds the monitors recover are fatalities.

Dark-eyed Junco – number four on the list


Why Are Birds Having This Problem?

  • Most migratory birds travel at night and navigate by the stars.
  • Artificial light attracts and disorients them
  • Glass is reflective – birds see sky and trees that are not there
  • Glass is transparent – birds see palm trees and other foliage growing inside the lobby
  • Gulls and crows have learned that small birds hit the buildings becoming easy prey for their morning meal.

Three times the number of birds die in the fall than in spring because the young birds are traveling south for the first time along with their parents. Many of the first year birds never make it.

Hermit Thrush – another frequent victim

Hermit Thrush

Lights Out Programs in Other “Enlightened” Big Cities

Other large cities have begun lights out programs . . . Boston, Washington DC, Twin Cities, Portland, Toronto, San Francisco, New York City, Baltimore, Charlotte.

The complete list of cities is here on the Audubon page.

What Can You Do To Help?

Does your city have a program? If not, encourage them to do so. Sadly, one of the largest cities along the Mississippi flyway still does not have a lights out program. I’m talking to you Cleveland. Recently a few buildings have individually decided to dim their lights.

Golden-crowned Kinglet – number ten on the list

Golden-crowned Kinglet

Window Decals

I have a very bird friendly yard with multiple feeders, nestbox, bird bath, and native plants. With all this air traffic, it is inevitable that I would have a few window strikes a year despite my efforts to prevent them.

This summer I tried a new deterrent – window decals.

What I See Looking Out . . .


Birds See My Reflected Yard When Looking In


I was skeptical, but it does work. I have not had a window strike since I added them in June. The decals have a reflective ultraviolet coating that birds can see and we cannot.


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Leave a Comment
  1. Mary / Sep 19 2015 12:56 pm

    We get a lot of window strikes so I’m interested in the decals.


    • Leslie / Sep 19 2015 1:01 pm

      I got them online at Amazon. They have a lot of different designs. Just make sure they have the ultraviolet coating that only birds can see.

      Liked by 1 person

  2. Suko / Sep 19 2015 4:49 pm

    I love your photos, Leslie. I’m glad the window decals work. 🙂


  3. Diane / Sep 19 2015 6:08 pm

    It hurts me when those guys strike a window as well;fortunately it’s a rarity.

    I love this guy –Golden-crowned Kinglet


    • Leslie / Sep 20 2015 11:20 am

      I almost never see them on the ground or staying still enough for a photo. I stumbled across a migrating flock that were so interested in the food on the ground that they didn’t care how close I came with the camera.


  4. BermudaOnion / Sep 19 2015 8:31 pm

    I love your weekend birding posts. I had no idea most migration is done at night. I don’t think we’ve had a window strike in this house.


    • Leslie / Sep 20 2015 11:22 am

      It is (apparently) safer for the little birds to fly at night, and air temperature is cooler. The large birds like geese, ducks, egrets, and cranes fly during the day.


  5. Vicki / Sep 20 2015 7:13 am

    I didn’t know most birds migrate at night. I’ve never had a bird hit a window but I have either blinds, curtains or window decals on all my windows.


  6. Beth F / Sep 21 2015 7:27 am

    We get a few window strikes a year –usually in the spring though.


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