Songbirds Can Sense Future Tornadoes from Miles Away

They're not psychic, but a group of songbirds can sense future tornadoes from miles away, flying the coop to avoid a devastating storm, according to a new study.

It goes to show that Mother Nature's early warning system may be better than our own advanced technology.

The feathered forecasters in question are golden-winged warblers living in the mountains of eastern Tennessee, who fled their breeding grounds one to two days before a massive storm system swept through the country back in April. Some 84 tornadoes rocked the central and southern United States, killing 35 people.

It should be mentioned that the storm was still 250-560 miles away when the warblers made a break for it; meanwhile our own Weather Channel was only just reporting that the storm was headed in our direction.

Even more astonishing, despite having just migrated a staggering 1,550 miles (2,500 kilometers) to reach their breeding ground destination, these tired birds showed no hesitation in leaving right away.

"We know that birds can alter their route to avoid things during regular migration, but it hadn't been shown until our study that they would leave once the migration is over and they'd established their breeding territory to escape severe weather," UC Berkeley ecologist Henry Streby, who led the study, said in a statement. "The warblers in our study flew at least 1,500 kilometers (932 miles) total to avoid a severe weather system. They then came right back home after the storm passed."

The findings were published in the journal Current Biology.

Tipped Off by Infrasound

Researchers would not have noticed this unplanned exodus had they not already been analyzing trackers attached to the birds to study their migration patterns.

So what exactly makes these warblers such great weathermen? Typically factors like barometric pressure, wind speeds on the ground and at low elevations, and precipitation trigger bird movement, however all these readings were stable at the time. The US Berkeley team suspects that infrasound from the tornadoes may be at play. (Scroll to read on...)

Infrasound is acoustic waves that travel through the ground and occur at frequencies below 20 hertz (cycles per second), which is too low for humans to hear. However, previous studies have suggested that birds and other mammals can hear infrasound generated by such events like volcanoes erupting, oceans crashing into shorelines, and in this case impending tornadoes. And the lower the frequency, the farther the sound waves can travel.

The scientists can't be sure that the warblers picked up on the infrasound waves, but it sure seems likely based on prior research.

"We may find that acoustics are a pretty significant way that birds in general view their environment, much like dogs use olfaction and humans use sight," added Jon Hagstrum at the US Geological Survey in California, who has studied infrasound use by pigeons.

This discovery could have important implications in the decades ahead, considering tornadoes are likely to become more severe with climate change.

"Evasive actions like the ones the warbler took might become more necessary," Streby said.

Warblers in Trouble

Golden-winged warblers regularly spend their winters in Central and South America before returning to North America's Great Lakes and Appalachian Mountain regions to breed. They have become of increasing concern to researchers given that their population is only five percent of historic levels in the Appalachians - their numbers are stable in the Great Lakes area, however.

Habitat loss is mostly to blame, while competition with Blue-winged warblers and cowbird parasitism are also factors at play, according to the American Bird Conservancy.

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