It’s well known that climate change is causing bird distributions to shift. A study published in the journal Global Change Biology suggests that that shift may be occurring far faster than anyone suspected.
According to researchers led by Brooke L. Bateman, of the University of Wisconsin Madison, landbirds that breed in the United States have been moving 1.27 kilometers (0.79 miles) a year, on average — about twice the pace described in earlier studies.
Even more surprising, the distributions of certain guilds of birds — migratory species, carnivores, insect eaters, and species that forage in the air and in the lower and upper canopies — are shifting even faster, write the researchers, some as much as 2.14 km (1.33 miles) a year.
Bateman and her colleagues compiled and cross-referenced six decades of detailed weather readings and breeding-bird locations to reach their conclusions. They used the data to generate monthly breeding-season distribution maps for 285 species of landbirds from April 1950 through July 2011.
“The general trend is that species distributions are shifting poleward and upslope in response to changing climate,” write the researchers, “but shifts are far from uniform and some species have shifted downslope or nonpoleward.”
The majority of distributions shifted west, northwest, and north. In general, the southern Plains and lower Midwest faced the greatest decline in ideal climate conditions, while the Dakotas, mid-Atlantic, and Pacific Coast showed the greatest increase.
“However, the degree to which changes in potential breeding distributions are manifested in actual species richness depends on landcover,” caution the authors. “Areas that have become increasingly suitable for breeding birds due to changing climate are often those attractive to humans for agriculture and development. This suggests that many areas might have supported more breeding bird species had the landscape not been altered.”
A version of this article was published in the April 2016 issue of BirdWatching.
Read the paper
Brooke L. Bateman, Anna M. Pidgeon, Volker C. Radeloff, Jeremy VanDerWal, Wayne E. Thogmartin, Stephen J. Vavrus, and Patricia J. Heglund (2015), The Pace of Past Climate Change vs. Potential Bird Distributions and Land Use in the United States. Global Change Biology. doi:10.1111/gcb.13154 (PDF).
More about climate change and birds:
Study: The deadly effect of climate change on Argentina’s youngest penguins (January 29, 2014).
Report: Climate change threatens birds across North America (June 18, 2013).
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