The climatic conditions needed by 285 species of land birds in the United States have moved rapidly between 1950 and 2011 as a result of climate change, according to a recent paper published in Global Change Biology.
The climatic conditions needed by 285 species of land birds in the United States have moved rapidly between 1950 and 2011 as a result of climate change, according to a recent paper published in Global Change Biology.
“Our goal was to look at the climate where these birds were observed breeding over this period and determine where that ‘sweet spot’ was moving as the climate changed in this period,” says first author Brooke Bateman, a post-doctoral researcher at the University of Wisconsin–Madison.
Warming temperatures are the fundamental alteration of climate change, and the researchers saw the expected northward expansion of suitable conditions, Bateman says, but also a considerable expansion to the west. Unexpectedly, the southern borders of suitable conditions did not, in general, move north, perhaps because a remnant population had not yet left that area.
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.
The study, the largest examination of the velocity of climate change for birds in the United States in the recent past, began by combining detailed weather records for the lower 48 states with data on the location of bird occurrences from the Global Biodiversity Information Facility. The researchers cross-referenced those data, creating a computer model of where the birds nest, in terms of climate factors like average and extreme temperature and precipitation.
In the face of climate change, a suitable climate for birds has been moving, on average, eight tenths of a mile per year—about twice the pace predicted by earlier studies.
The researchers then used the model to predict where the same climate conditions for those birds would be located in 2011, reflecting the ensuing changes in climate. Finally, using data from the 2011 North American Breeding Bird Survey, they checked their work.
The results show that in the face of climate change, a suitable climate for birds has been moving, on average, eight tenths of a mile per year—about twice the pace predicted by earlier studies.
To make sense of their data, the researchers lumped bird species into guilds—groups based on shared factors like diet, foraging location and migration habits. Hospitable climate moved relatively fast for short- or long-distance migrants, carnivores, insect eaters, and birds that foraged in the air or the canopy of trees. Slow-moving guilds included permanent residents, herbivores, omnivores, hummingbirds and birds that forage on tree bark, such as woodpeckers.
Continue reading ath the University of Wisconsin-Madison.
Birds wading image via Shutterstock.
