Birds sensed devastating US tornado and fled one day ahead

Golden-winged warblers have very sensitive hearing

A man places an American flag in front of what is left of his brothers house after it was destroyed when a tornado hit in Louisville, Mississippi (Joe Raedle/Getty Images)

Birds nesting on the path of an incoming tornado, which devastated parts of the US, “evacuated” their home one day before, scientists say.

Geolocators attached to the birds showed that they fled the Appalachian Mountains and flew 700km (400 miles) south to the Gulf of Mexico in April 2014.

The next day, a devastating wave of tornadoes spread across central and southern US states, killing 35 people.

Writing in the journal ‘Current Biology’, ecologists said they believe that the tiny, five golden-winger warblers were able to predict the extreme event because of their keen low-frequency hearing.

Scientists were particualarly impressed that the warblers made the lengthy journey despite having completed their seasonal 5,000km (3,100mile) migration from Colombia just days before.

Dr Henry Streby, from the University of California, Berkeley, said he initially set out to see if tracking the warblers was even possible.

"This was just a pilot season for a larger study that we're about to start," Dr Streby told BBC News.

"The fact that they came back with the geolocators was supposed to be the great success of this season. Then this happened!"

Each summer, the birds nest and breed in regions encompassing the Great Lakes and the Appalachian Mountains.

As part of an on-going study, Dr Streby and his colleagues from the Universities of Tennessee and Minnesota tagged 20 golden-winged warblers in May 2013, in the Cumberland Mountains of north-eastern Tennessee.

In April 2014, 10 of the tagged warblers returned from their seasonal migration, as the team observing them received advance warning of the tornadoes and evacuated from their building.

Following the storm, the scientists used the geolocators –small devices which measure light levels - to track where five of the birds had flown.

The scientists found that the birds had taken precautionary action, beginning one to two days ahead of the storm's arrival, while it was still hundreds of miles away.

By 2 May, all five were back in their nesting area.

Remarkably, the warblers' evacuation commenced while the closest tornado was still hundreds of miles away.

The new study is the first time that migratory birds have been seen taking such dramatic evasive action.

“We know that birds can alter their route to avoid things during regular migration,” Dr Streby told the broadcaster. “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.”