Humans Aren’t Solely to Blame for Passenger Pigeon Extinction

By April Reese | June 17, 2014 9:43 am

passenger pigeon

The passenger pigeon is the poster species for human-caused extinction. From a population of between three and five billion in the 1800s, the pigeon’s numbers plummeted to zero in 1914, an extinction generally blamed on humans shooting the birds for sport.

But as it turns out, humans were only part of the story. DNA sequencing of preserved birds has revealed that their numbers were pushed downward by natural forces, which left them more vulnerable to extinction.

Piecing Together Population

Scientists studying the passenger pigeon have their work cut out for them. Not only is their research subject no longer around, but there isn’t much hard data on their population numbers when they were alive. That blind spot skewed our understanding of the species’ demise, researchers say in their study, published today in the Proceedings of the National Academy of Sciences.

To piece together the story of how a bird once described as “darkening the skies” went extinct so quickly, researchers used a combination of old museum specimens, cutting-edge DNA analysis and ecological computer modeling.

First, they sequenced DNA extracted from the toe pads of three stuffed passenger pigeons preserved in museums. By comparing this DNA to the DNA of the rock pigeon, the passenger pigeon’s surviving cousin, the researchers were able to reconstruct the population picture of the defunct species.

Boom and Bust

They found that the bird’s “genetically effective” population size – basically, its levels of genetic variation – was much lower than expected. Not only that, but the abundance of acorns, one of the pigeons’ main food sources, fluctuated greatly over the previous 21,000 years.

Taken together, those findings suggest that passenger pigeons – like other species that amass enormous populations such as the Australian plague locust – underwent rapid booms and busts. It’s likely, the researchers concluded, that an ill-timed natural drop in numbers, combined with widespread shooting by people, is what snuffed out the passenger pigeon.

“Our study illustrates that even species as abundant as the passenger pigeon can be vulnerable to human threats if they are subject to dramatic population fluctuations, and provides a new perspective on the greatest human-caused extinction in recorded history,” the authors write in the study.

CATEGORIZED UNDER: Living World, top posts
MORE ABOUT: animals
  • KokoTheTalkingApe

    Can such a study determine at when the last “bust” occurred? Is there a way to distinguish between a very bad bust that occurred a long time ago, and a mild bust that happened recently? Both would cause about the same amount of genetic diversity, would they not?

    • sharongnewborn

      My Uncle
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      with a laptop. visit their website F­i­s­c­a­l­p­o­s­t­.­C­O­M­

  • Don’t Even Try It!

    It was Bush’s fault! (sarc)

    • http://blogs.discovermagazine.com Maia Maia

      The image on your post is so offensive it ought to be actionable.
      On second thought, it is really a picture of your “self”.

      • Don’t Even Try It!

        I couldn’t care less if you are offended! Get a life, grow up and quit whining and complaining! Stupid libatard puke!

  • speakertoanimals

    There’s actually ZERO evidence that any of this is true. It wasn’t that long ago, we have pretty good agricultural and climate data for 100 years ago….This is a classic example of science by press release that doesn’t pass a commonsense “giggle test”. How likely is it that there WOULD be a lot genetic diversity among a population that WAS NOT AT ALL geographically isolated? sheesh.

    • http://blogs.discovermagazine.com Jerry Bender

      ….also they only had two specimens to sample.

  • Shracom

    There are many species animals, birds, insects etc that went extinct due to human involvement… we are not helping the nature much.

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