Bird numbers plunge in U.S. and Canada: study
Scientist Peter Marra has been bird calling for years.
But these days some of those calls are going unanswered.
(SOUNDBITE) (English) PETER MARRA, DIRECTOR OF THE GEORGETOWN ENVIRONMENT INITIATIVE, SAYING:
"Sometimes there are a variety of warblers that are migrating through here in the fall but right now I don't really see many."
That's because many of the birds he's followed are disappearing.
Those disappearances are detailed in a new study published Thursday in the journal Science.
For 50 years, researchers tracked populations of more than 500 species using bird counts and migration patterns.
Marra of Georgetown University's Georgetown Environment Initiative was a co-author of the study.
(SOUNDBITE) (English) PETER MARRA, DIRECTOR OF THE GEORGETOWN ENVIRONMENT INITIATIVE, SAYING:
"And what we found was staggering. It was depressing. That there was a decline in over 29 percent of birds. 3 billion birds lost over those 50 years. Birds that make up some of the most common species we see: red wing black birds, warblers, thrushes, eastern meadowlarks, a whole suite of species across diverse families. It was quite depressing."
The study says people are to blame.
It cites habitat loss and degradation, agricultural chemicals killing insects found in birds' diets, and even outdoor hunting by pet cats.
Shorebirds, like the Sanderling, dropped a third in 50 years.
Agricultural intensification has hit grassland birds particularly hard.
Those birds, like the Western Meadlowlark, saw their population almost halved.
Marra says these losses are a warning for humans.
(SOUNDBITE) (English) PETER MARRA, DIRECTOR OF THE GEORGETOWN ENVIRONMENT INITIATIVE, SAYING:
"Birds are the quintessential ecosystem indicators. They are the canaries in the coal mine. When something's going wrong with birds, something's going wrong with the environment. It's just not healthy."
Despite the decline, Marra says there's still a chance.
(SOUNDBITE) (English) PETER MARRA, DIRECTOR OF THE GEORGETOWN ENVIRONMENT INITIATIVE, SAYING:
"Put policies in place that are going to protect these animals that we share in our common home. These birds will respond. They'll respond rapidly. In five or ten years, we can see these species start to increase. It can happen that fast. Nature is resilient. We just need to give them a chance."
