Bird populations are dropping sharply across North America, a trend that has researchers concerned about a “mass extinction event”.
According to a new study, nearly 3 billion birds have disappeared from North America over the last 50 years, a drop of 29 percent. Researchers say the drop applies not only to threatened or endangered species, but also common “backyard birds”.
Scientists fear the drop is evidence that Earth is in the middle of a sixth “mass extinction” event that threatens up to a million plant and animal species.
