Birds in the United States are not only declining, but they are declining faster, especially in areas with intensive agriculture, according to new research.
Overall drops in bird population, measured from 1987 to 2021, were sharpest in warm and warming areas, suggesting that climate change may play a role. The study, published on Thursday in the journal Science, shows only correlation with intensive agriculture and temperature, not causation.
It does not factor in other circumstances that may be affecting birds along migratory routes or while they are overwintering.
But it adds to an ever more robust body of evidence that birds — one of the best measured families of animals on Earth, and a sentinel for the health of other species — are not OK.
Whatever the specific drivers, the accelerating losses make sense given society’s focus on economic growth, which often comes at a cost to the natural world, said Peter P.
Marra, an ornithologist and dean at Georgetown University who specializes in bird populations and was not involved with the new research.
“The American dream turns into the American nightmare as we start to look at what we’re doing to biodiversity and systems that we depend on as humans,” he said. In 2019, Dr.
Marra and a team of scientists published landmark findings that the number of birds in the United States and Canada had fallen by 2. 9 billion, or 29 percent, since 1970.
Thursday’s study relied on one of the same data sources, the North American Breeding Bird Survey, a monitoring project led in part by the United States Geological Survey. Observers count birds along designated routes of roughly 25 miles each.
To analyze rates of decline, the new research was limited to 1,033 routes that offered yearly or almost yearly counts, and ultimately included 261 bird species. We are having trouble retrieving the article content. Please enable JavaScript in your browser settings.
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