Birds have the ability to sense a storm from hundreds of miles away and fly away a day before the storm hits. A new research on golden-winged warblers revealed that five warblers evacuated their nesting place a day before the April 2014 tornado. Geo-locator tracking data showed that the birds left the Appalachians and fled about 400 miles south to the Gulf of Mexico.
Scientists used geolocators to track birds
These delicate, tiny birds knew that a massive storm, including high winds and tornadoes, was on its way one or two days in advance. Next day, storms swept across the central and southern U.S., killing 35 people and causing more than $1 billion in property damages. After the storm, scientists recaptured warblers and removed the geolocators.
Geolocators are small devices that measure light levels. Depending on the length of the day and timing these half a gram devices record, researchers can calculate and track the location of migratory birds. In a study led by Dr Henry Streby of the University of California, Berkeley, all the five warblers tagged with geolocators took immense evasive action, one or two days ahead of the storm’s arrival.
How do birds sense it?
The birds flew south of the tornadoes’ path, and then went home again, Dr Streby told BBC News. The warblers began evacuating while the nearest tornado was still hundreds of miles away. Weather conditions in their nesting region were absolutely normal at the time, so there would have been few detectable changes in temperature, atmospheric pressure or wind speed. So, how did they sense it?
Well, birds have the ability to hear sounds that we humans can’t. Birds can hear infrasounds, the deep rumble that tornadoes produce. Infrasounds are simply acoustic waves that occur at frequencies below 20Hz, well below what humans can hear. Besides tornadoes, events like ocean waves crashing, winds blowing and volcano eruptions at faraway distances also create infrasounds that birds can sense.
Dr Streby said warblers are unlikely to be the only species doing this. Findings of the study were published in the journal Current Biology.