The number of birds in the United States and Canada has declined by 3 billion, or 29 percent, over the past half-century, scientists find. A continent-wide weather radar network also reveals a similarly steep decline in biomass passage of migrating birds over a recent 10-year period. - discu.eu

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The number of birds in the United States and Canada has declined by 3 billion, or 29 percent, over the past half-century, scientists find. A continent-wide weather radar network also reveals a similarly steep decline in biomass passage of migrating birds over a recent 10-year period. https://science.sciencemag.org/content/early/2019/09/18/science.aaw1313 7 comments 19/9/2019 science