Parrots are amazing birds that have bright colors and charming personalities, but they are also the most at risk of extinction.
A new study showed that many parrot species that used to live in the Caribbean have disappeared, and some of the ones that are left are not as special as we thought.
What Ancient DNA Tells Us About Parrot Evolution and Distribution
The researchers discovered that two species of Amazona parrots, which now live only on Cuba and Hispaniola, were once more varied and widespread across the Caribbean islands.
The results help us understand how parrots became the most endangered group of birds in the world, with more than a quarter of all species facing extinction.
This is especially true for island parrots.
When Christopher Columbus first arrived in the Caribbean in 1492, he saw that there were so many parrots that they "blocked out the sun."
Today, more than half of the parrot species in the Caribbean are extinct, from big multicolored macaws to a tiny parrotlet.
It is hard to conserve the remaining parrot species because we don't know much about where they used to live. This is partly because their history with humans is very complex.
"Parrots have always fascinated people," said Jessica Oswald, the main author of the study and a senior biologist with the U.S. Fish and Wildlife Service Forensics Lab. "Indigenous peoples have moved parrots around continents and islands for thousands of years. Later, European colonists did the same thing, and we still do it today."
Because of this long history of exchange and trade, it is not easy to know how parrots ended up where they are now.
Half of the 24 parrot species that currently live in the Caribbean were brought from other places, and we don't know if native parrots evolved on the islands they live on or were also moved there by humans.
Luckily, their popularity with humans means that we can sometimes find parrots in archaeological sites as well.
Their bones have been found in piles of trash - called middens - along with shells, fish bones and other leftovers from ancient meals.
Parrots also have a good fossil record in the Caribbean, compared to other tropical regions.
However, their fossils are usually not complete. Often, their bones are broken or separated, and it's hard to tell which species they came from.
DNA can give us clear answers when physical comparisons are not enough, and co-author David Steadman wanted to see if they could get any genetic material from the bone tissue.
Using genetic sequencing methods, the researchers found links between extinct flightless Caribbean birds and those in Africa and New Zealand.
They also compared ancient DNA from Caribbean parrots with genetic sequences from modern birds.
They found that two species of Amazona parrots, which are currently restricted to Cuba and Hispaniola, were once more diverse and widespread across the Caribbean islands.
How Humans Caused Parrot Extinction and How They Can Prevent It
The researchers think that human activities, such as hunting, destroying habitats, and bringing invasive species, have caused many Caribbean parrot species to decline and go extinct over time.
They also think that human movements of parrots between islands may have changed their genetic diversity and evolutionary history.
"Parrots are very adaptable birds," Oswald said. "They can live in different habitats and use different resources. But they are also sensitive to human impacts. We need to know their past to protect their future."
The study shows the importance of using different types of evidence, such as fossils, archaeology, and genetics, to reconstruct the history of biodiversity and biogeography in the Caribbean.
It also gives useful information for conservation efforts of the remaining parrot species in the region.
