August 29, 2017 by Sarah Nightingale
Two species of songbirds that once made a home in the Bahamas likely became extinct on the islands because of rising sea levels and a warmer, wetter climate, according to a new study by researchers at the University of California, Riverside and the University of Florida, Gainesville. The study, which was published today in the Proceedings of the National Academy of Sciences, presents a historical view of how climate change and the resulting habitat loss can affect Earth's biodiversity.
Titled "Origin, Paleoecology and Extirpation of Bluebirds and Crossbills in the Bahamas Across the Last Glacial-Interglacial Transition," the authors are Janet Franklin, distinguished professor of biogeography in UCR's College of Natural and Agricultural Sciences, and David Steadman, curator of ornithology at the Florida Museum of Natural History at the University of Florida.
The Eastern Bluebird (Sialia sialis) and Hispaniolan Crossbill (Loxia megaplaga) were among 17 species of birds that were found on the Bahamian Island of Abaco during the last Ice Age, but that no longer live there today. Both species are still alive elsewhere, with the former found in continental North America and the latter in Hispaniola. Fossil records from Abaco suggest that these birds resided on the island year-round, as opposed to migrating there in winter.
"The abundance of fossils, the presence of young birds among the fossils, and the evolution of a shorter wingspan in the Eastern Bluebird all suggest that these birds did not migrate to the island but were a resident population. But then they disappeared," Franklin said.