Do some animals have a "sixth sense" that allows them to predict things like earthquakes or the weather? According to scientists who are studying the migration patterns of the golden-winged warbler, the answer is yes, at least in regards to the weather, reports the Guardian.

After retrieving trackers that were fitted to a group of warblers, researchers noticed an odd pattern in the data. As the birds approached the southern United States on their way back from wintering in South America, they took a sharp detour, as if to avoid some invisible obstacle in their path.

It just so happens that there was good reason for the birds to steer awry. A massive storm was brewing across the region, one that would eventually spawn more than 80 tornadoes and kill as many as 35 people. That the birds should attempt to avoid this danger is not surprising. What's surprising is that they appeared to detect the storm long before encountering it. The warblers adjusted their migration route when they were still well over 500 miles and several days away from the storm.

How did the birds know there was a storm approaching?

"We looked at barometric pressure, wind speeds on the ground and at low elevations, and the precipitation, but none of these things that typically trigger birds to move had changed," said David Andersen at the University of Minnesota. "What we’re left with is something that allows them to detect a storm from a long distance, and the one thing that seems to be the most obvious is infrasound from tornadoes, which travels through the ground."

Infrasound is low-frequency sound that is typically below the normal limit of human hearing. Storms can make these sounds, which can carry over large distances. Scientists aren't certain that the warblers picked up infrasound waves from the storm, but they aren't sure what else could have tipped them off. 

"In five to six days, they all made this big move around the storm," said Andersen. "They all went south east in front of the storm, and then let it go by, or moved behind it. It was individual behavior, they were several hundred kilometers away from each other most of the time."

The fact that the birds veered around the storm as individuals rather than as a group is particularly telling. It indicates that each bird is capable of detecting the storm independently. So this was not simply a case of a flock being led off course. These birds clearly had some way of detecting the coming danger.

The discovery is good news for the warblers, which can be found nesting throughout the Appalachian region of North America. 

"With climate change increasing the frequency and severity of storms, this suggests that birds may have some ability to cope that we hadn’t previously realized. These birds seemed to be capable of making really dramatic movements at short notice, even just after returning on their northwards migration," said Andersen.

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