Tyto furcata – the American barn owl. Credit: Wikimedia Commons

Here’s something strange about barn owls. They’re not technically “true owls.”

That distinction belongs to the family Strigidae, which includes most of the familiar hooting owls. Barn owls belong to a different family, Tytonidae. They’re still owls, of course, but their evolutionary history is surprisingly different.

And according to a new genetic study, their ancestors may have pulled off one of the most extraordinary journeys in bird evolution.

A stunning journey to the Caribbean

Millions of years ago, barn owls apparently reached the Americas not by crossing ancient land bridges, as scientists once suspected, but by flying across the Atlantic Ocean.

Their first destination wasn’t North or South America. It was the Caribbean.

There, the birds established themselves, evolved into distinct lineages, and eventually spread across both continents. The study also sheds light on a lost world of enormous Caribbean owls, some standing around a meter tall, and uncovers evidence that barn owls reached the remote Galápagos Islands on two separate occasions.

All of this was hiding in DNA preserved in museum collections.

This is what a barn owl looks like without feathers (Tyto alba – western barn owl). Credit: Wikimedia Commons

Today, barn owls live on every continent except Antarctica. They’re remarkably successful birds, able to thrive in environments ranging from tropical grasslands to farmland, and temperate woodlands.

But their presence in the Americas was pretty surprising for biologists.

For decades, scientists considered two main explanations. Perhaps the owls traveled from Asia across Beringia, the ancient land bridge connecting Siberia and Alaska. Or perhaps they took a northern Atlantic route, using ancient landmasses and islands between Europe and North America.

Both possibilities had a problem.

Barn owls aren’t particularly fond of snow

Their preferred hunting grounds are open landscapes where they can locate small mammals. Deep snow makes that difficult, and high-latitude environments can be especially challenging for them.

“Barn owls are tropical and temperate,” David Steadman, an ornithologist at the Florida Museum of Natural History, explained in a statement. “They can’t handle high latitudes where there’s snow. So, coming over to the Americas via Beringia or the North Atlantic via some blend of Iceland, Greenland and Canada never seemed realistic.”

To investigate, Min Zhao and colleagues analyzed DNA from dozens of barn owl specimens preserved in 11 museums. Some specimens dated back to 1876.

The researchers analyzed two types of DNA: one from the cell’s nucleus, which contains most of its genetic information, and another from mitochondria, the tiny structures that supply energy to cells. By comparing genetic differences between specimens, they reconstructed the owls’ evolutionary family tree.

The results pointed overwhelmingly toward the Caribbean.

Tyto glaucops – the ashy faced owl, found in Haiti and the Dominican Republic. Credit: Wikimedia Commons

The islands contain some of the oldest surviving branches of the American barn owl lineage. Their owls also display much greater genetic differences than populations spread across the American continents.

“Looking at their modern distributions, barn owls are widespread across continental America but not so much in the Caribbean,” Zhao said in the Florida Museum release. “So, you would assume that the Caribbean barn owls came from the continent, right? But actually, based on genetics, we found that the most divergent lineages are in the Caribbean.”

The analysis suggests that Eurasian and Western Hemisphere barn owls diverged approximately five million years ago. The actual ocean crossing probably occurred later, during or shortly before the Pleistocene ice ages. The American barn owl lineage itself appears to have originated in the Caribbean less than two million years ago.

Tyto furcata pratincola – a subspecies of American barn owl that inhabits much of North America, from southern Canada to northern Mexico, as well as Bermuda, the Bahamas, and Hispaniola in the Caribbean. Credit: Wikimedia Commons

But could an owl really cross an ocean?

In 1722, English naturalist Mark Catesby reported seeing an owl hovering over his ship halfway between Africa and America. The bird struggled to find somewhere to land before disappearing over the ocean. That observation cannot establish the route ancient owls took, but it illustrates their capacity for remarkable long-distance flights.

The findings build on earlier genetic research into barn owl evolution, revealing a much more detailed history of their expansion through the Americas. And the Caribbean proved to be more than a convenient stepping stone.

The Giant Owls

Ever heard of the chickcharney?

According to Bahamian folklore, this strange, giant, owl-like creature haunts the islands, bringing good luck to those who treat it kindly and terrible misfortune to those who don’t. One particularly chilling legend claims that the chickcharney can snatch people away, leaving behind nothing but a single shoe.

But the Bahamas really were once home to enormous owls. One species, Tyto pollens, stood roughly a meter tall, towering over the barn owls we know today. Scientists suspect these formidable birds may have inspired the chickcharney legend.

Prehistoric Caribbean islands supported an extraordinary variety of owls, including Tyto ostologa, another giant species known from fragmentary fossil remains on Hispaniola.

But this remarkable world eventually collapsed.

At least six barn owl species that once inhabited the Caribbean are now extinct, according to the study. Many of the native mammals they hunted also disappeared after humans began settling the islands thousands of years ago.

Hunting, habitat destruction, and invasive species devastated the Caribbean’s wildlife. The researchers suspect the giant owls disappeared primarily because they lost their prey, rather than because people hunted the birds themselves.

However, the precise timing and causes of their extinction remain uncertain. The researchers also failed to recover usable DNA from the giant owl fossils, leaving their evolutionary relationships unresolved.

Whether the chickcharney legend preserves a distant memory of these extraordinary birds remains a mystery. But archaeological evidence from the Lesser Antilles suggests that humans and giant owls really did cross paths.

The Galápagos Hold One Last Surprise

Tyto alba punctatissima – The Galápagos barn owl. Credit: Wikimedia Commons

The DNA analysis also uncovered an unexpected story in the Galápagos Islands, roughly 1,000 kilometers off Ecuador’s coast.

Barn owls apparently colonized the islands twice.

The first lineage arrived from the Caribbean during the middle Pleistocene, apparently bypassing the continental Americas. These birds eventually developed distinctive physical and genetic characteristics.

Much later, another population arrived from South America, establishing itself on San Cristóbal.

The descendants of the first lineage still survive on two of the Galápagos Islands, but have disappeared from another following human settlement in the 19th century.

Its genetic differences are so substantial that the researchers argue it deserves recognition as a separate species, Tyto punctatissima, rather than merely a subspecies of the American barn owl. Recognizing an island population as a unique evolutionary lineage could encourage efforts to protect it before it disappears.

The study reveals a striking paradox: The Caribbean helped barn owls conquer the Americas, yet lost much of the extraordinary diversity it produced. But the giant predators that once ruled these islands were real, and their surviving relatives still carry evidence of one of the most remarkable ocean crossings in bird evolution.

The study was published in the journal Proceedings of the Royal Society B.