Acceleration hotspots of North American birds’ decline are associated with agriculture

Key findings from this study

This research indicates that:

• 47% of analyzed bird species exhibit significant population declines, with more than half of these showing acceleration of decline rates.
• Acceleration hotspots concentrate geographically in the Mid-Atlantic, Midwest, and California, overlapping with regions of highest agricultural intensity.
• Spatial patterns of accelerating decline indicate agricultural intensity may function as a primary driver of continent-wide bird population loss.

Overview

This research quantifies population abundance declines and acceleration patterns across 261 North American bird species using 35 years of survey data, establishing spatial correlations between accelerating decline hotspots and agricultural intensity.

Methods and approach

Analysis integrated 1033 Breeding Bird Survey routes documenting abundance change from 1987 to 2021. The study examined temporal trends and acceleration rates for 261 species across 54 avian families and 10 habitats. Researchers mapped spatial patterns of decline and acceleration to identify geographic hotspots.

Results

Continental bird abundance declined on average across local survey routes. Decline hotspots concentrated in southern and warm North American regions, while acceleration hotspots emerged in the Mid-Atlantic, Midwest, and California. Agricultural intensity patterns spatially matched these acceleration hotspots.

Of 261 species analyzed, 122 species (47%) exhibited significant declines. Among declining species, 63 demonstrated acceleration of decline and 67 showed declining per-capita growth rates. This indicates that a substantial portion of North American bird populations face compounding population pressures. The acceleration pattern was not uniformly distributed geographically but concentrated in regions characterized by intensive agricultural practice.

Implications

Spatial alignment between agricultural hotspots and bird decline acceleration suggests that agricultural intensity functions as a primary driver of contemporary population loss. This finding implicates specific regions and land-use practices in bird population dynamics, enabling targeted conservation assessment. The prevalence of accelerating declines across nearly half of declining species raises urgent concerns about population viability thresholds.

These results indicate that bird population loss represents an ongoing and intensifying threat rather than a stabilized trend. The identification of acceleration hotspots permits resource allocation toward regions and species combinations at greatest risk. Future research should disentangle specific agricultural mechanisms—pesticide use, habitat fragmentation, crop monoculture—driving observed acceleration patterns.

Scope and limitations

This summary is based on the study abstract and available metadata. It does not include a full analysis of the complete paper, supplementary materials, or underlying datasets unless explicitly stated. Findings should be interpreted in the context of the original publication.