Over the past 50 years, the conservation movement in North America has famously helped protect some of the most iconic birds from extinction, including bald eagles, wild turkeys, white pelicans, peregrine falcons, Kirtland’s warblers, and California condors. But a new study in the journal Science shows that while those rare birds were recovering, total bird numbers were plummeting, even among some of the most common backyard species.
The results of the study are shocking, even for the researchers. In total, bird populations have declined by 2.9 billion individuals, representing a 30 percent drop in total breeding bird numbers.
The researchers found broad population decreases, not just with rare or threatened birds. “We saw that these losses occurred in the common species and across every habitat,” Rosenberg says. “Even birds we were calling generalists that should be well-adapted to human environments were in decline. Starlings and house sparrows, these invasive species that we thought may be taking over, were showing the same declines. That overall result was, to me, a big surprise.”
Long-time feeder watchers have likely noticed the declines as well. Dark-eyed juncos, which are one of the most abundant birds across the United States in winter, have declined by 168 million individuals. Eastern and western meadowlarks, whose song used to be part of the backdrop of rural America, have dropped by 139 million, or 75 percent; the white-throated sparrow and its classic “Oh, Canada, Canada” call has plummeted by 93 million. Two out of every five Baltimore orioles are gone, and the same is true for barn swallows.3 Billion Birds Across Many Species Have Disappeared in North America | Sierra Club