Migratory birds bear brunt of climate-changed weather
January 12, 2010 by Terry Devitt (PhysOrg.com) — As global climate change fuels more frequent and intense hurricanes and droughts, migratory birds, especially those whose populations are already in decline, will bear the brunt of such climate-fueled weather, suggest a pair of new studies. Writing in the December online issue of the journal Global Change Biology, researchers from the University of Wisconsin-Madison describe the effects of intense, climate-charged weather on North America’s birds. The studies, which focused on the influence of drought and forest-leveling hurricanes, show that neotropical migrants — birds that spend the winter in tropical or subtropical regions of North, Central and South America and breed in temperate North America — are most vulnerable to the growing risk of severe weather. “Extreme climate events are increasing in frequency and intensity,” explains Anna Pidgeon, a UW-Madison professor of forest and wildlife ecology and a senior author of both of the new studies. “We’re seeing a decrease in abundance in response to drought and hurricanes, especially with species that have small populations.” The study of the influence of drought on birds looked at the effects of prolonged dry spells on birds in a 15-state region centered on the U.S Great Plains. In that study, the Wisconsin researchers coupled data from the North American Breeding Bird Survey with precipitation measurements gleaned from more than 1,600 weather stations during a period of about 15 years beginning in 1989. In addition, the study utilized seasonal greenness measurements as recorded by satellite. “The effects of drought get stronger as you look at uncommon birds,” explains Thomas Albright, the lead author of the drought study and postdoctoral fellow at UW-Madison. In particular, drought seems to weigh most heavily on neotropical migrants. “We found those decreasing in quantity compared to average birdlife overall.” …
