Francois Leroy and colleagues at Ohio State University published a peer-reviewed study in the journal Science on February 26, 2026, showing that the rate at which North American bird populations are shrinking has itself been speeding up since the mid-1980s. The research analyzed 261 species across 1,033 monitoring routes and found acceleration hotspots concentrated in agricultural regions of the Midwest, California, and the Mid-Atlantic. The findings build on a widely cited 2019 estimate that the continent had already lost 3 billion birds since 1970, and they shift the scientific conversation from documenting losses to explaining why those losses are getting worse.
Decades of Data Reveal a Worsening Trajectory
The study drew on the long-running Breeding Bird Survey, a volunteer-driven monitoring network managed by the U.S. Geological Survey that uses standardized point-count protocols along fixed routes across the United States and Canada. According to the Ohio State research team, the analysis covered the period 1987 to 2021 and applied multi-factor statistical testing to separate genuine acceleration from ordinary year-to-year noise. That methodological step matters because earlier research, including a landmark 2019 study by Rosenberg, established that bird populations had fallen by 29 percent since 1970 but did not assess whether the annual rate of decline was itself changing.
The distinction between a steady decline and an accelerating one carries real consequences for conservation planning. A stable rate of loss allows managers to project when a species might reach a critical threshold and intervene accordingly. An accelerating rate compresses that timeline, meaning populations could cross danger points sooner than linear models predict. By demonstrating acceleration across most bird families, the Leroy study signals that existing projections of future bird numbers may be too optimistic and that conservation targets based on linear trends may underestimate the urgency of intervention.
Farming Regions Are the Sharpest Pressure Points
The geographic pattern in the data points directly at agriculture as a primary driver. Acceleration hotspots cluster in parts of the Mid-Atlantic, including Delaware, Maryland, and New Jersey, as well as in the Midwest and California, according to the study published in Science. These are areas where row-crop farming, pesticide application, and fertilizer use have intensified over the same decades that bird losses picked up speed. The overlap is not coincidental: the study’s statistical framework tested agricultural variables alongside climate and land-use factors, and farming practices emerged as a consistent correlate of faster declines.
Pesticides and fertilizers affect birds through several linked pathways. Insecticides reduce the prey base for species that depend heavily on insects for food, while herbicides strip away the weedy margins and wildflower patches where many ground-nesting birds breed. Fertilizer runoff degrades wetland and riparian habitat, compounding the pressure. One gap in the current evidence, however, is the absence of direct field measurements linking specific pesticide compounds to population drops at the hotspot level. The Science paper establishes strong statistical associations, but causal confirmation at the chemical level would require targeted fieldwork that has not yet been published, leaving room for future studies to refine which practices are most damaging and which changes would yield the quickest gains.
Forest Birds Stand Apart, but Nearly Everyone Else Is Struggling
Christopher Tonra, an ecologist at Ohio State University involved in the research, framed the results bluntly: “Except for forest birds, almost every group is doing poorly. So we need to ask ourselves a question. How do we protect these groups?” The relative resilience of forest species likely reflects the fact that mature forest cover in the eastern United States has been stable or increasing for decades, providing a buffer that open-country and wetland birds do not enjoy. Forest birds also benefit from large public landholdings where development pressure is lower and some logging practices have shifted toward longer rotations and retention of key habitat features.
That exception should not be mistaken for good news across the board. Grassland birds, shorebirds, and aerial insectivores, species that hunt flying insects on the wing, are among the hardest-hit groups. Their habitats overlap heavily with the agricultural zones flagged as acceleration hotspots, and many migrate long distances, exposing them to multiple stressors across continents. The practical implication is that conservation strategies focused on protecting forest tracts, while valuable, will do little to slow the broader crisis. Addressing the decline requires engaging with the agricultural sector on pesticide regulation, habitat set-asides, and farming practices that leave room for the insects and nesting cover that most declining species need, as well as international cooperation along migratory flyways.
What Accelerating Losses Mean Beyond Birds
Birds are not just charismatic wildlife; they perform ecological work that directly supports human food systems. Insect-eating species suppress crop pests, raptors control rodent populations, and pollinators like hummingbirds contribute to plant reproduction. When these populations thin out faster each year, the services they provide weaken in tandem, potentially increasing reliance on chemical controls and driving a feedback loop of more intensive farming and further biodiversity loss. One researcher quoted in coverage of the study put the stakes in stark terms: “The American dream turns into the American nightmare as we start to look at what we’re doing to biodiversity and systems that we rely on.” That language reflects a growing view among ecologists that bird declines are an early warning of broader environmental stress, not an isolated problem confined to a few sensitive species.
The raw monitoring data that underpins this analysis is publicly available through the Patuxent data portal, where annual results are released via ScienceBase and smaller extracts can be retrieved through an online system. Open access to the Breeding Bird Survey dataset means independent researchers, state wildlife agencies, and conservation groups can replicate the Ohio State team’s methods or apply them to local questions, such as identifying which landscapes within a state are seeing the steepest accelerations. That transparency is one reason the BBS has remained the backbone of North American bird science for more than five decades, enabling both peer-reviewed studies and on-the-ground management decisions.
From Science to Action on a Changing Continent
Although the new study focuses on birds, it slots into a broader body of U.S. Geological Survey work that documents how human activity is reshaping ecosystems and natural hazards. USGS publications, such as a circular on ecosystem sustainability, emphasize that biodiversity loss, water quality degradation, and land-use change interact in complex ways. The accelerating declines in bird populations are one manifestation of those intertwined pressures, highlighting how decisions in sectors like agriculture and urban development can ripple through food webs and ecosystem services. In parallel, USGS monitoring of earthquakes, floods, and other hazards underscores that environmental change is not limited to biology; physical systems are also in flux, and communities must plan for multiple, overlapping risks.
For the public, one way to connect with these issues is through the lands and waters managed by federal agencies, where many of the continent’s remaining strongholds for birds are found. The U.S. Geological Survey supports partner agencies by providing mapping, monitoring, and interpretive tools that help guide management on national parks, wildlife refuges, and other public lands. Visitors who purchase recreation passes gain access to many of these areas, where they can witness both the richness that remains and the gaps where species have vanished. That direct experience can make abstract statistics about billions of lost birds feel immediate and personal, potentially building support for policies that reduce pesticide use, restore wetlands, and protect remaining grasslands.
Tools, Data, and Public Engagement
Behind the scenes, a suite of federal resources helps translate scientific findings into concrete decisions. The USGS operates an online information service where students, landowners, and local officials can ask questions about topics ranging from wildlife surveys to water resources, making it easier for non-specialists to interpret technical reports. For those interested in maps, imagery, and printed materials that can support education or land-use planning, the agency’s map store offers topographic products, aerial photographs, and other geospatial tools. These resources allow community groups and local governments to overlay bird data with land-cover maps, zoning information, or floodplains as they weigh conservation options.
Other USGS platforms track environmental change in real time, illustrating how biological and physical systems intersect. The agency’s interactive earthquake map, for example, shows where seismic activity is occurring around the globe, reminding users that landscapes are dynamic and occasionally subject to abrupt disturbance. While earthquakes are not a primary driver of bird declines, the same mapping and monitoring infrastructure that supports hazard assessment also underpins surveys of habitats, water resources, and climate variables. Together, these tools create a picture of a continent in motion, with its species, land uses, and physical processes all changing at once, and underscore why the accelerating loss of birds is best understood as part of a larger story about how humans are reshaping the environments on which they, and the birds, depend.
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*This article was researched with the help of AI, with human editors creating the final content.
