How songbirds respond to changing weather

Weather data sets and bird surveys from past years in the Badlands and prairie regions of the United States can give researchers clues about the future of songbird species.

In a recent study published in The Condor: Ornithological Applications, lead author Jessica Gorzo, a PhD candidate at the University of Wisconsin-Madison, and her team compared weather and climate data from 1965 to 2010 in the Dakotas, Montana and Wyoming with songbird abundance data collected from the North American Breeding Bird Survey during the same years.

The team looked at 14 grassland songbird species including species of sparrows, sandpipers and others that they knew from previous research in 1988 had suffered as a result of drought in the Midwest. They found that some songbird species are particularly vulnerable to weather patterns caused by climate change such as precipitation increases or decreases. For instance, both the grasshopper sparrow (Ammodramus savannarum) and the Baird’s sparrow (Ammodramus bairdii) — which prefer precipitation in lush, dense grasslands — faced the steepest declines as a result of weather changes. This could spell trouble for weather-sensitive species found in regions that are projected to have hotter and drier weather conditions as a result of climate change, she said.

In addition, three other species — the Vesper sparrow (Pooecetes gramineus), eastern kingbird (Tyrannus tyrannus) and upland sandpiper (Bartramia longicauda) — also responded significantly to weather conditions, according to Gorzo. Vesper sparrows and eastern kingbirds responded slightly negatively to increasing precipitation whereas upland sandpipers responded positively to increasing temperature. These three responses indicate the species favor drier conditions, Gorzo said.

As a potential solution, Gorzo recommends implementing measures that could benefit several of these species. For instance, managers should take note of species that require tallgrass prairie such as the Baird’s sparrow and consider implementing strategies that would mitigate drought effects early in the season. This would promote the grassland conditions that Baird’s and grasshopper sparrows need, she said. Gorzo also suggests looking at habitat heterogeneity. “In mixed grass prairies where the study was done, we should maintain tall grass and have a variety of mid height and short grass for all of the species in that region,” she said.

Gorzo continues to study songbirds in the central U.S. grasslands and is now looking at how grassland species respond to weather compared to forest species.

She feels fortunate to have used the North American Breeding Survey program to come up with important conservation implications for the future. “It is a tremendous volunteer effort that takes skill, dedication and hard work,” she said in a press release. “To be able to put it to good use to elucidate some patterns relevant to climate change felt really rewarding, and I can’t thank birders over the decades enough for working year in and year out to add to this dataset.”