Bahama Oriole population much larger than previously thought

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Bahama Oriole

On a low-lying island in the Caribbean, the future of the critically endangered Bahama Oriole was just getting brighter. A new study by researchers from the University of Maryland-Baltimore County (UMBC) estimates the population of these striking black and yellow birds to be around 1,300 to 2,800 individuals in the region they studied, suggesting that the overall population is likely is several thousand. Older studies estimated the total population to be less than 300, so the new results show that there are at least ten times as many Bahamian orioles as previously thought. The research appeared in Avian Conservation and Ecology this week.

The research team shares its findings with Birdlife International, the organization that makes recommendations to the International Union for Conservation of Nature (IUCN) about birds on the Red List of Threatened Species. The new findings could lead the IUCN to downlist the Bahama Oriole, who only lives on the island of Andros in the Bahamas, from critically endangered to endangered.

In 2017, Hurricane Irma devastated the Bahamas and aroused fears of the oriole and many other birds on the islands.

The new result “is a step forward for conservation,” says Michael Rowley, UMBC 2018 alumnus and one of two co-lead authors on the study. “This will make the world a little better informed about what to focus on. There are other birds that could use your attention. “

A fresh look at the Bahama Oriole

In addition to freeing up resources to protect other endangered birds in the Caribbean, details of the study revealed new ways to protect the still-endangered Bahama Oriole. Previous work had largely excluded the pine forest, which covers approximately 20 percent of the island, as an important habitat for the Bahama Oriole. Instead, researchers focused on human-dominated habitats such as villages and agricultural land.

However, a 2018 study conducted by 2017 UMBC alumnus Daniel Stonko improved this understanding of Bahama Oriole ecology. Stonko and colleagues reported the first three Bahamian oriole nests ever recorded in the pine forest. A 2019 follow-up study led by UMBC alumna Briana Yancy conducted more detailed nesting site features for the orioles on Andros and found that they prefer pine forests with straw palms.

Support local efforts

The latest study builds on these two projects. The research team conducted bird counts at 467 locations covering 713 square kilometers in the northern 25 percent of the island. They chose locations along abandoned and previously unmapped forest roads to strike a balance between easy access and lack of human influence on the presence of the birds. The team found that the strongest predictor of oriole frequency was the presence of pine forests. Nesting habitat studies, including Yancy’s, suggest that the birds are most common in pine forests with plenty of straw palms in the undergrowth during the breeding season.

“The orioles seem to be able to nest in many different habitats, which is very good and important for the orioles to know,” says Kevin Omland, professor of life sciences at UMBC and lead author of all three studies. “It gives us really useful information about what the breeding habitat is like for us to let the IUCN know.”

The new findings also provide vital information for the local environmental protection efforts of the Bahamas National Trust (BNT), which was a key partner of the Omland Research Group during its longstanding work in the Caribbean.

“If the BNT is able to create or expand national parks, it could try to add more pine forest with these tall straw palms to the undergrowth,” says Omland.

Lasting effect

The other co-lead author, Richard Stanley of the University of Florida, performed most of the personal bird counts for the new study using maps developed by the Omland team. Rowley then took on the lead of an intricate statistical analysis with the assistance of Colin Studds, professor of geography and environmental systems at UMBC, and scientists at the Smithsonian Migratory Bird Center.

The extremely impactful results are particularly exciting for a researcher like Rowley, who finished his research as a student and is still in the very early stages of his scientific career. Before joining Omland’s group, Rowley said, “I’ve never been outside of the adjacent US. “It was an incredible privilege and it really opened me up to my current interest in conservation work.”

Regarding the results themselves: “It’s amazing. How many people can work on a project when they are a student who has such real impact while being able to do field work, work with animals, and get involved in the community? “Says Rowley. “It’s really great to know that the work we’ve done is such an exciting influence.”

Thank you to the University of Maryland-Baltimore County for providing this news.

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