Golden-winged warblers apparently knew in advance, long before it was sensed by people, that a large and deadly tornado-spawning storm was forming and decided to take flight
The storm would go on to spawn 84 confirmed tornadoes and kill at least 35 people in the US.
Scientists suspect the birds knew to leave by listening to infrasound associated with the severe weather, which occurs at a level well below the range of human hearing.
According to a report in the journal Current Biology, the discovery was made by accident while researchers were testing whether warblers could carry geo-locators on their backs.
With a big storm brewing, the birds took off from their breeding ground in the Cumberland Mountains of eastern Tennessee, where they had only just arrived.
The warblers travelled 1,500 kms in five days to avoid the historic tornado-producing storms.
“The most curious finding is that the birds left long before the storm arrived,” says Henry Streby of the University of California, Berkeley.
“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.”
The birds fled from their breeding territories more than 24 hours before the arrival of the storm.
The researchers suspect that the birds did it by listening to infrasound associated with the severe weather, at a level well below the range of human hearing.
“Meteorologists and physicists have known for decades that tornadic storms make very strong infrasound that can travel thousands of kilometres from the storm,” Streby says.
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