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Birds are rapidly vanishing from North America, with dramatic population losses in places that were once thought safe.
Date : May 02 . 2025
Great egrets and little blue herons. Blue-winged warblers and yellow-bellied sapsuckers. Snowy owls and tropical kingbirds.
A recent comprehensive study reveals that three-fourths of bird species in North America are experiencing population declines, highlighting a gradual extinction crisis that poses a threat to entire ecosystems.
The declines among the continent's avian species—such as red-winged blackbirds calling out in marshes, chickadees flocking to suburban feeders, and peregrine falcons soaring between city skyscrapers—should act as a warning signal for those living near these birds, according to scientists.
For many bird species, the most significant population drops observed between 2007 and 2021 occurred in areas where they were previously most plentiful, indicating that even in their strongholds, birds are facing challenges.
“That was the most concerning finding,” said Johnston.
This study builds on research from 2019 that utilized radar data to reveal that North America had lost over 3 billion birds from 1970 to 2017. However, the new study does not update that figure or assess whether the overall decline in bird populations is accelerating. Instead, it provides a detailed geographic analysis of population trends for nearly 495 bird species.
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Johnston’s team examined a comprehensive online database known as eBird, which gathers over 100 million bird sightings each year from both professional ornithologists and amateur birdwatchers worldwide. “Birders have been keeping logs in their journals for over a century. It’s just part of the birdwatching experience,” noted Ken Rosenberg, a retired conservation scientist at the Cornell Lab of Ornithology and a member of the team that created and launched eBird in 2002. “There was always this dream of what we could achieve by harnessing all that information.”
Using a machine learning model to account for changes in how people observed birds over time, the researchers found that 75 percent of the documented species were in decline. This alarming statistic reinforces the known pattern of mass decline among bird populations. Richard Gregory, a professor at University College London who was not involved in the research, commented on the findings, stating, “Taken as a whole, and depressingly, the heavy weight of evidence points towards a worsening situation for North American birds.”
There is no single reason for this emerging silent spring. Many grassland species are losing their habitats to expanding agricultural lands, which are also inundating these areas with pesticides that eliminate the insects that many birds rely on for food. Along coastlines, construction and other human activities are encroaching on vital beaches and wetlands where birds feed and nest. In the Arctic, rising temperatures are altering critical breeding habitats, further threatening avian populations.
Despite the grim overall picture, there are still reasons for hope within the findings. For the majority of bird species analyzed in the study, there are specific regions where subpopulations remain stable or even show signs of growth. This detailed analysis can provide valuable insights for scientists and government officials, helping them understand the factors that enable certain birds to thrive and informing conservation strategies aimed at protecting entire species.
However, challenges remain. The federal government under President Donald Trump has been advancing regulatory changes that weaken a century-old law designed to protect migratory birds. These changes allow for increased mining, construction, and other activities that could destroy the habitats of endangered birds and other species.
Amanda Rodewald, a Cornell ecologist who co-authored the study, highlighted that many of the same pressures affecting bird populations—such as climate change and air pollution—also have detrimental effects on human health and well-being. “Humans share those same environments,” Rodewald remarked. “So if they’re not healthy enough for birds, they’re unlikely to be healthy enough for people, too.”