Agricultural Regions Showing Accelerated Decline in Bird Populations

The Midwest, California, and Mid-Atlantic states are areas of agriculture intensity, as indicated by the amount of cropland and the use of fertilizer and pesticides. These are also the regions where bird population decline is most accelerated, according to a study led by François Leroy, a postdoctoral scholar in evolution, ecology and organismal biology at The Ohio State University. The team considered a range of factors with potential to affect bird abundance but, as Leroy explains, “What we found was that agriculture intensity was the main predictor of those hotspots of accelerated decline.” Leroy notes, “The impact is not only on a few species with the same traits or only on farmland bird species. Twice as many species showed accelerating decline compared to decelerating decline, and the same pattern was seen at the family level. That means it is occurring at a very large taxonomic scale – a lot of different species with different functional traits are affected, and it’s systemic.” Declines in bird populations affect many parts of the ecosystem, including insect populations, seed dispersal, and the food chain for wildlife.”

Related ATTRA publication: Beneficial and Pest Birds: Vertebrate IPM Tip sheet