A tiny songbird that weighs a mere 4.2 ounces can fly nonstop over the north Atlantic in just 72 hours, researchers have found.

For 50 years, scientists have debated whether blackpoll warblers are able to make the marathon flight from New England to South America, or if the birds require breaks to complete the journey.

While birds like sandpipers and seagulls make lengthy migrations, unlike blackpoll warblers, these birds have long wings and are able to settle on water to rest. Blackpoll warblers would likely drown if they touched the sea.

To solve the mystery of these birds' autumn migration, researchers attached tiny backpack flight recorders to 40 of them in 2013 to track their flight paths. However, because of the geo-locators' size, they weren’t able to transmit the data remotely.

Only five of the devices were recovered from birds in Vermont and Nova Scotia the next spring, but they contained enough data to prove that blackpoll warblers fly over the Atlantic.

While some of the birds may stop to rest in Bermuda or the Antilles, others fly nonstop, making a journey that could range from 1,400 to 1,700 miles.

"We're really excited to report that this is one of the longest nonstop overwater flights ever recorded for a songbird, and finally confirms what has long been believed to be one of the most extraordinary migratory feats on the planet," Bill DeLuca of the University of Massachusetts Amherst told The Telegraph.

To prepare for the epic journey, blackpoll warblers build up fat stores by eating as much as possible. In some cases, they even double their body mass in fat.

"For blackpolls, they don't have the option of failing or coming up a bit short," said Ryan Norris of the University of Guelph. "It's a fly-or-die journey that requires so much energy."

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