Chart of the Day: Causes of Bird Mortality

Scientists estimate up to 1 billion birds meet untimely demise thanks to illuminated buildings. Light pollution of the airspace is a relatively recent but growing threat to nocturnally migrating birds. Minneapolis ranks among the top 10 cities posing the greatest dangers to birds in this most recent study, authored by researchers at Cornell University, along with cities like Los Angeles, Chicago, Houston and St. Louis.

You may wonder, how else do birds die? This 2003 chart from the Sibley Guide to Birds suggests that the life of a bird has many hazards:

Bird Mortality Chart

Windows have long been a source of peril for the modern migratory bird per this 2003 chart of bird mortality.

Numerous buildings in Minnesota participate in the Audubon Society’s Lights Out program each year. Through this program, buildings commit to turning off their lights during spring and fall migration periods between midnight and dawn; participating buildings include the Minnesota Capitol complex, as well as many notable buildings in Minneapolis, the suburbs, Rochester and Duluth. The spring program period goes from March 15 to May 31. This program also conserves energy. Find out more at the Minnesota Audubon Society, and visit BirdCast for daily maps of migration patterns. is a non-profit and is volunteer run. We rely on your support to keep the servers running. If you value what you read, please consider becoming a member.

5 Responses to Chart of the Day: Causes of Bird Mortality

  1. Adam Miller
    Adam Miller April 11, 2019 at 1:50 pm #

    Does the chart leave out non-feral cat predators or are those not a significant source of bird mortality?

    • Julie Kosbab April 11, 2019 at 9:19 pm #

      I think “all cats” were considered feral in this study. If your cat is outside and kills a bird…

      • Adam Miller
        Adam Miller April 12, 2019 at 9:15 am #

        Surely there are non-cat predators, though.

  2. Jonathan Foster April 15, 2019 at 11:11 am #

    How does habitat destruction no get listed?

  3. Serafina Scheel
    Serafina Scheel April 16, 2019 at 11:15 am #

    For updated estimates, I thought this piece was really interesting, highlighting how much remains a mystery:

    From the article: “They found that most supercolliders are migratory species and that most urbanadapted species are not vulnerable to collisions. … Based on 10 different
    data sources, they demonstrate that skyscrapers and other large buildings kill the most birds on a per building basis, but individual residences cumulatively kill the most birds

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