What the study found
The study found that North American bird abundance has declined on average across local survey routes, and that many of these declines are speeding up rather than slowing down. The authors also report hotspots of accelerating decline in the Mid-Atlantic, Midwest, and California, alongside areas of decline in southern and warmer parts of North America.
Why the authors say this matters
The findings indicate that a large part of North American bird populations may be at risk because many declines are not just continuing but accelerating. The authors suggest that the spatial match between accelerating decline and agricultural intensity points to agriculture as a possible driver of this trend.
What the researchers tested
The researchers analyzed abundance change and the acceleration of that change using 1,033 North American Breeding Bird Survey routes. They examined 261 bird species, 54 avian families, and 10 habitats over the period from 1987 to 2021.
What worked and what didn't
Across the continent, the average abundance of birds declined per local route. Of the 122 species with significant declines, 63 also showed acceleration of decline, and 67 showed declining per-capita growth rate.
What to keep in mind
The abstract does not describe specific study limitations beyond the scope of the survey routes, species, families, habitats, and time period analyzed. The agricultural connection is presented as an association in the spatial patterns, not as a direct causal test.
Key points
- Average bird abundance declined across North America from 1987 to 2021.
- Hotspots of accelerating decline were reported in the Mid-Atlantic, Midwest, and California.
- These accelerating decline patterns matched areas of agricultural intensity.
- 122 species showed significant declines, and 63 of them also showed acceleration of decline.
- The study analyzed 1,033 Breeding Bird Survey routes across 261 species.
Disclosure
- Research title:
- Bird decline is accelerating in agricultural regions
- Authors:
- François Leroy, Marta A. Jarzyna, Petr Keil
- Institutions:
- Czech University of Life Sciences Prague, Czech University of Life Sciences Prague, The Ohio State University, The Ohio State University
- Publication date:
- 2026-02-26
- OpenAlex record:
- View
Get the weekly research newsletter
Stay current with scholarly research without reading academic papers — one filtered digest, every Friday.