A new study suggests there are at least 10 times as many Bahamian Orioles as previously thought, and offers insights that could benefit future conservation efforts for orioles and other Caribbean bird species
On a low-lying island in the Caribbean, the future of the endangered Bahama Oryol is brighter. A new study led by researchers at the University of Maryland, Baltimore County (UMBC) estimates the number of these amazing black and yellow birds to be somewhere between 1,300 and 2,800 individuals in the area surveyed, indicating that the total population is likely to be several thousand. Older studies estimated the total population to be less than 300, so the new findings indicate that there is at least 10 times as many Bahamas Orioles as was previously understood. The research appeared this week in Preserving birds and the environment.
The research team is sharing its findings with Birdlife International, the organization that makes recommendations to the International Union for Conservation of Nature (IUCN) on birds included on its Red List of Threatened Species. The new findings may affect the IUCN to list the Bahamas Oriole, which only lives on Andros Island in the Bahamas, from endangered to endangered.
Michael Rowley, a 2018 UMBC graduate and one of the study’s co-authors, says the new finding “is a step forward for conservation.” “This makes the world more aware of what we should put our efforts towards. There are other birds that can also attract attention.”
In addition to freeing up resources to protect other endangered birds in the Caribbean, details of the study reveal new ways to protect the still endangered Bahama Oryol islands. Previous works had greatly reduced the pine forests, which cover about 20 percent of the island, as an important habitat for the Bahama Oriole. Instead, the researchers focused on human-dominated habitats such as villages and farmland.
However, a 2018 study led by Daniel Stonko, a University of California, London graduate in 2017, overturned this understanding of the Bahama Oriol ecology. Stonko and colleagues report the first three nests from the Bahama Oriole were recorded in a pine forest. A follow-up study led by 2019 UMBC alumna Briana Yancy, published in December 2020, further detailed characteristics of the nest site for oriole in Andros, and found that they prefer pine forests with palm trees.
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The latest study draws on both projects. The research team conducted a census of birds at 467 sites over an area of 713 square kilometers in the north of 25 percent of the island. They chose locations along previously abandoned and unassigned logging routes, to balance ease of access and lack of human influence on the presence of birds. The team found that the strongest predictor of willow abundance was the presence of pine forests. Nesting habitat studies, including the Yancy study, indicate that during the breeding season, birds may be more common in pine forests with lots of palm trees in their basement.
“The orioles appear to be able to nest in quite a few different habitats, which is really good for orioles and it’s important to know,” says Kevin Ommland, professor of biological sciences at UMBC and lead author on all three studies. “It gives us really useful information about what the nesting habitat looks like, so we can tell the IUCN.”
The new findings also provide important information for local conservation efforts led by the Bahamas National Trust (BNT), which has been a key partner of the Omland Research Group throughout its long-term work in the Caribbean.
“If BNT is able to create or expand national parks, it might try to include more pine forests with tall thatched palms in the basement,” says Omland.
Another co-lead author, Richard Stanley of the University of Florida, conducted most of the personal bird numbers for the new study, using maps developed by Omland’s team. Rowley then took the lead in a complex statistical analysis with support from Colin Studes, professor of geography and ecosystems at UMBC, and scientists at the Smithsonian Migratory Bird Center.
The high-impact results are especially exciting for a researcher like Rowley, who completed the research as an undergraduate and still very early in his scientific career. “I wasn’t outside the neighboring United States,” says Rowley, before joining Omland. “It was an incredible privilege, and it really opened up to me my current interest in restoration work.”
As for the results themselves, “It’s amazing. How many people are working on a project when they’re a college student and have such an impact on the real world, while also being able to do fieldwork, work with animals, and participate in the community?” Says Rowley. “It’s really cool to know that the work we’ve done has had such an exciting effect.”