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3 billion birds have been lost in U.S. and Canada since 1970

Illustration of vanishing bird
Illustration: Aïda Amer/Axios

Human activity has decimated roughly 29% (almost 3 billion) of bird populations over the past 50 years in the U.S. and Canada, including meadowlarks, swallows and sparrows, scientists announced Thursday.

Why it matters: In addition to suffering pervasive losses in several groups of birds, North America has also reached a "widespread ecological crisis" that is affecting other activities like spring migration, food production and pest control, the scientists warn.

What's new: In a study published Thursday in Science, scientists found that "we're losing species of birds, abundances of birds, much faster than we thought ... almost three billion or one-third since 1970," co-author Peter Marra tells Axios.

  • The biggest driver is habitat loss caused by humans for agriculture and urbanization. This is something policymakers can still restore, for the most part, says Marra, former director of the Smithsonian Migratory Bird Center (SMBC) and now director of the Georgetown Environmental Initiative (GEI).
  • Marra urges people to take action in "the voting booth" and "not stand for the repeal of things that protect our water and land."
  • People also need to remove threats to birds by reducing lawn areas that don't provide bird habitat, minimizing light pollution and avoiding the use of harmful pesticides. Outdoor cats have also played a significant role.

The bad news: The study, which uses a combination of standardized surveys by bird enthusiasts and data from radar, finds the abundance of birds has fallen in diverse areas since 1970.

  • 12 bird families — including sparrows, warblers, blackbirds and finches — have 90% of the total accumulated loss.
  • Grassland birds have been hit the hardest, showing a 53% reduction (more than 720 million) in population.
  • Shorebirds, which often reside in sensitive coastal habitats, "were already at dangerously low numbers and have lost more than one-third of their population," the press release states.
  • Radar measures over the past decade show the volume of spring migration dropped 14% over that period.

The good news: The study also notes prior actions taken to protect certain species have worked, with waterfowl and raptors in particular becoming more abundant.

  • With wetland protections and hunting regulations, waterfowl like ducks, geese and swans have restored their populations, Marra says.
  • And due to endangered species protections and the removal of DDT-based pesticides, raptors like the bald eagle have become more plentiful.

What they're saying: "Studies like this do suggest the potential of a systems collapse,” Richard Gregory, a professor at University College London who wasn't part of this study, told the Washington Post. "These birds are an indicator of ecosystem health. And that, ultimately, may be linked to the productivity and sustainability of agricultural systems.”

The bottom line: Marra says it isn't too late to restore habitats and restore a healthy ecosystem in North America.

Of note: Sponsors of the study include American Bird Conservancy, Bird Conservancy of the Rockies, the Cornell Lab of Ornithology, Environment and Climate Change Canada, GEI and SMBC.

Go deeper: Listen to Science's podcast on this topic and check out a new multimedia website describing the issue and advocating action, called 3BillionBirds.org.