In late April 2014, a powerful storm system ripped through the southern and central United States. More than 80 confirmed tornadoes impacted the area, killing 35 people.
A population of golden-winged warblers in eastern Tennessee left their nesting grounds 1-2 days before the tornado outbreak. The birds migrated more than 400 miles to the Gulf of Mexico.
How did the birds know? Acoustic waves. Specifically, below 20 hz.
Acoustic waves below 20 hz fall into an area known as infrasound. Researchers know that birds and other animals can hear infrasound. The lower the frequency, the farther these sound waves can travel.
These golden-winged warblers ‘heard’ the supercell storms coming while they were still several hundred miles away.
“It is the first time we’ve documented this type of storm avoidance behavior in birds during breeding season,” said Henry Streby, a UC Berkeley ecologist and leader of the research team.
Sterby went on to say, “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.”
Humans are no stranger to using infrasound waves. The UC Berkeley press release highlights how we use infrasound arrays around the world to detect nuclear bomb explosions. Officials use it to make sure countries are following the Comprehensive Nuclear Test Ban Treaty.
Now we just need a few of these arrays parked in tornado alley. Can’t hurt to have another data point along with current severe weather prediction models.
“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,” said Streby.
Image credit: Gunnar Kramer