How North America lost nearly 3 billion birds over the last 50 years

Scientists have released a stark new warning about the disappearance of billions of birds in the U.S. and Canada. A new study published in the journal Science says more than a quarter of the entire bird population disappeared over the last half-century — that's a loss of nearly 3 billion birds in the past 50 years.

Peter Marra, senior author and director of the Georgetown Environment Initiative, called the loss of birds an "environmental crisis" and said it should serve as a "wakeup call."

"This is a horrible situation, and it's about time people wake up and started taking care of their environment," Marra said. "Because it's an environment that we also depend on."

The study brought together information gathered since 1970, much of which was collected by thousands of volunteer bird enthusiasts from across the U.S. and Canada.

Grassland birds like sparrows and goldfinches took the hardest hit, losing more than half their population; shorebirds lost more than a third of their numbers.  

Researchers aren't sure what's making the birds so vulnerable. But they pointed to human actions, including the destruction of birds' natural habitats and the use of toxic pesticides.

"When we lose them it's like burning the yard. It's like tearing down our museums. We're losing our heritage," Marra said. "So our children and their children, these future generations will not be able to share, you know, watching these flocks of birds that we once watched."

"To me, it tells us that that we're a little sick, we need to get back on the mend," said Marcos Trinidad, director of the Audubon Center at Debs Park. He added that the birds are the "canary in the coal mine."