No, it ain’t wind turbines.
Using data from the North American Breeding Bird Survey, the authors found that about half of the 261 species analyzed showed significant declines from 1987 to 2021, and a quarter showed accelerating declines. Hotspots of accelerating abundance decline were located in regions with high-intensity agriculture (high cropland area, fertilizer use, or pesticide use)
The first notable finding is that warm and warming regions coincide with areas of abundance decline (ΔN, Fig. 3, A and C, and figs. S7 and S8). This pattern is consistent with the evidence that bird populations are shifting their distributions northward as they track cooler conditions (31). Increases in temperatures have been shown to increase the risk of bird species’ extinction as a result of a lack of species adaptability to rapidly changing climatic conditions (32), and consistent temperature-related responses have been documented across both Europe and North America (33). Our results further support this by showing that areas experiencing greater warming (Fig. 3C) also exhibit stronger abundance declines, suggesting that rising temperatures may be a driver of recent bird population losses.
The second major finding is that the hotspots of negative Δg (and Δr), i.e., the acceleration of the decline (Fig. 2D and fig. S5B), coincide with areas of high-intensity agriculture—namely those with high fertilizer or pesticide use or large areas of croplands (26) (Fig. 3, B and D, and figs. S7 and S8). These three variables are strongly correlated (fig. S4) and we cannot separate their independent effects, and so we interpret them collectively as indicators of agricultural intensity. The coincidence between agricultural intensity and acceleration of bird abundance decline is concerning, especially given the increases in North American agricultural production, and farm size, during the past 40 years (34).
We also found an interaction between agricultural intensity (i.e., pesticide use, fertilizer use and/or cropland area) and temperature change in their effect on Δg (fig. S9): The negative effect of agricultural intensity on Δg is stronger in areas with more pronounced temperature increase. Indeed, agricultural landscapes are known to warm more than natural areas as a result of reduced vegetation cover and altered surface properties (35, 36), which may amplify climate-driven stress on birds