Rare dove is not related to any other birds we know today

At first glance, the Cuban blue-headed quail dove appears ordinary. It has brown feathers, a slender beak, and a characteristic strut like other doves.

Compared to Cuba’s colorful parrots, it might seem unremarkable. However, this bird has long puzzled biologists. Scientists have struggled to determine its origins, how it arrived on the island, or what species it is related to.

For the first time, researchers have sequenced the bird’s DNA to uncover its history. Instead of clear answers, they found more confusion.

“This species has been an ornithological enigma for a very long time,” said Jessica Oswald, a Florida Museum of Natural History consultant staff affiliate and lead author of the study.

“We focused on this dove species because we were anticipating an odd result that may help us understand the complex biogeography of the Caribbean. We did not anticipate it being so unique from an evolutionary perspective relative to anything else.”

A unique evolutionary lineage

Scientists once believed the blue-headed quail dove was related to doves and pigeons from Central and South America. Some features, however, seemed more similar to birds from Australasia. Recent genetic analysis has disproved both theories.

The study shows that this dove is not closely related to species in Australia or the Americas. Instead, it stands apart from all known doves and pigeons.

“This species is even more evolutionarily distinct than the dodo was,” Oswald said. The dodo, also a type of dove, had at least one close relative, the Rodrigues solitaire, before both went extinct.

DNA evidence, along with fossil analysis, suggests that the blue-headed quail dove’s lineage may be as old as 50 million years. In comparison, humans and chimpanzees diverged just 5 to 6 million years ago.

The history of Caribbean extinctions

Oswald conducted this research as part of a broader National Science Foundation initiative to understand bird extinctions in the Caribbean.

About 12% of all Caribbean bird species have disappeared since humans arrived. These include a nearly four-foot-tall giant owl, over a dozen parrot species, a raptor larger than a bald eagle, a flightless ibis that fought with its wings, and a condor with a powerful bite.

Scientists have struggled to determine how these extinct birds relate to modern species. Oswald developed new methods to extract and sequence DNA from fossils, helping connect extinct and living birds.

Early tests on a Caribbean cave rail fossil revealed a previously unknown evolutionary link to birds in Africa, New Guinea, and New Zealand. A later study showed that a parrot, now restricted to Hispaniola, once lived across the Caribbean before human activity reduced its range.

Cuban dove is nearing extinction

Though not extinct, the blue-headed quail dove faces serious threats.

“There are 1,000 mature individuals of this species left in Cuba. It is threatened by overhunting by people, habitat loss and invasive species like cats. It’s very much on the brink,” Oswald said.

Due to its rarity, no one had sequenced its DNA before. Most specimens in North American museums were collected decades ago, making DNA extraction difficult.

Oswald used a technique she developed for fossils, applying it to a toe pad from a specimen collected in 1958, and anxiously awaited the DNA results.

“She called me up and said, ‘Are you sitting down?’ I thought she was going to tell me they didn’t get any good sequencing and had no data, but it was just the opposite,” said study co-author David Steadman, former curator of ornithology at the Florida Museum.

Value of museum specimens

Steadman spent decades witnessing advancements in DNA technology. He sees this study as proof that museum collections remain vital for modern research.

“It’s another instance of the importance of museums and the long-term maintenance of specimens. As ancient DNA techniques have improved, we find that fossils, historical and modern specimens are even more useful than before.”

Oswald and Steadman were surprised by the results. Other Caribbean doves have known origins, with ancestors from North, Central, or South America. The blue-headed quail dove, however, remains a mystery.

Cuban dove may be the last of its kind

“It’s a relictual species and has probably been in the Caribbean for a long time. Cuba is an old island,” Steadman said.

The dove’s origins remain uncertain. It may be the last survivor of an ancient lineage, as genetic evidence suggests, or an isolated offshoot of another dove species stranded in Cuba long ago.

Despite its preference for ground living, its ancestors likely had the strong flight ability that allows doves and pigeons to spread across vast distances.

“There are some groups of birds that are spectacular dispersers, one being pigeons and doves. They just get up and go,” Oswald said. “Many are particularly good dispersers because they eat a lot of fruit and sometimes have to move large distances to look for fruiting trees.”

The future of the Cuban dove

The blue-headed quail dove remains an evolutionary puzzle. While its origins are uncertain, its future is even more precarious.

With its population dwindling, conservation efforts may be the only way to prevent it from following the dodo into extinction.

Researchers from multiple institutions contributed to this study, including Bret Boyd from Virginia Commonwealth University, Avery Szewczak and Julie Allen from Virginia Tech, Michelle LeFebvre and Rob Guralnick from the Florida Museum of Natural History, and Brian Stucky from the University of Florida.​

The study is published in the journal Biology Letters.

Image Credit: Florida Museum photo by Kristen Grace.

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