from the IOW:-tornado's-infrasonic-warbles-warned-warblers dept.
Osvaldo Nunez reports that a recent study out of UC Berkeley says that golden-winged warblers can predict the coming of storms and tornadoes while the closest tornado is still hundreds of miles away. In April, a massive thunderstorm ravaged central and southern United States, causing more than $1 billion in damage across 17 states. The birds nest and breed around the Great Lakes and the Appalachian Mountains every summer. After flying 1,500-miles down to Tennessee, two days before the storms, flocks of songbirds and golden-winged warblers departed the areas and flew 900-miles to Florida and Cuba. They escaped just south of the tornadoes' path - and then went straight home again. By May 2, five tagged birds were back in their nesting area. "At the same time that meteorologists on The Weather Channel were telling us this storm was headed in our direction, the birds were apparently already packing their bags and evacuating the area," says Henry Streby.
The most likely tip-off was the deep rumble that tornadoes produce, well below what humans can hear. Noise in this "infrasound" range travels thousands of kilometers, and may serve as something of an early warning system for animals that can pick it up. "It's very unlikely that this species is the only group doing this," says Streby. The new study is the first time that migratory birds have been seen taking such dramatic evasive action. "We know that birds can alter their route to avoid things during regular migration. But it hadn't been shown before that they would leave once the migration is over, and they'd established their breeding territory, to escape severe weather." With the predicted increase in severity and frequency of similar storms as anthropogenic climate change progresses, understanding large-scale behavioral responses of animals to such events will be an important objective of future research.