Birds can sense and evade harsh weather before it arrives

It seems that birds may have a sixth sense when it comes to oncoming tornadoes.

An intriguing new study out of University of California, Berkeley, has found that birds actually flee their nesting grounds one or two days ahead of the arrival of severe supercell storms.

“It is the first time we’ve documented this type of storm avoidance behaviour in birds during breeding season,” said biologist Henry Streby, lead author of the study published this week in the journal Current Biology.

The research team followed the movements and behaviour of golden-winged warblers in the mountains of eastern Tennessee using geolocators placed on their backs and ID bands attached to their legs. In late April 2014, when a massive storm system blew across the United States and generated 84 tornados, the tagged warblers were found to fly at least 930 miles to avoid the storm, even though it was still some 250 to 560 miles away.

What makes this so incredible is that at that distance, there were still no signs of local environmental changes like temperature, atmospheric pressure or even wind within any of the warblers’ breeding territories.

“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,” Streby said in a press statement.

But how exactly were the birds alerted to the oncoming severe weather? Streby and his team believe it may have something to do with underground sound waves.

Low-frequency sounds can travel long distances. For instance, sound produced by nuclear bomb detonations can be detected around the world through a network of monitors set up by the Comprehensive Nuclear Test Ban Treaty.

Scientists have known for years that tornadoes can produce intense infra-sounds that travel through the ground, but this is the first time this link with bird evacuations has been made.

But its not just birds that appear to be Mother Nature’s alarm systems. Zoo animals also tend to act strangely when storms are on the way.

"They may spend more time in their dens or more time pacing. They just know something is up,” Erica Miller, an adjunct associate professor at the University of Pennsylvania School of Veterinary Medicine told NBC News.

And there is other anecdotal evidence of many wild species, even including fish and insects, that can predict weather changes. For instance, ladybugs congregate before heat waves set in, and sharks are drawn to columns of water that are associated with rapid temperature changes stirred up by storms, according to Discovery News.

Some researchers are pointing to animals’ ability to possibly smell ozone produced by storms or detect drops in barometric pressure. There is no doubt that animals have evolved to adapt to changing environments – like squirrels knowing when to store acorns or bears knowing when its time to hibernate.

But now there is also a growing body of evidence that many species indeed do have the sense to detect severe weather changes in order to survive.