Dr. David Steadman, associate director for Research and Collections at the University of Florida, and curator of Ornithology at the Florida Museum of Natural History, spoke about natural and human factors that brought about the extinction of birds on Abaco.
With collaboration and research provided by Brian Kakuk, Nancy Albury and Janet Franklin, fossils taken from several sites on Abaco were compared to determine the rates of extinction and survival in birds within two time periods. During the Pleistocene-Holocene transition (PHT), which took place at the end of the Ice Age, 17 of the 59 (29 percent) Ice Age birds known to have lived on Abaco did not survive.
Dr. Steadman pointed out that the losses of birdlife were a result of changes in climate, habitat, sea level rise and the shrinking of land area. On his slide presentation, Steadman illustrated how much bigger The Bahamas was before sea level rise and its proximity to Florida and Cuba because of its larger size.
He added that another considerable impact to loss of birdlife was with the arrival of humans on Abaco some 900-1,000 years ago. In that time, 38 percent of birds became extinct. This time habitat change was the likely cause.
It was fascinating to see how well preserved the fossils at Sawmill Sink, and according to Dr. Steadman, they represent an unparalleled quality of preservation in this region. Fossils of the Albury’s Tortoise and Cuban crocodile were found along with fossils of critters eaten by barn owls discovered at 9,500 feet depth.
At Gilpin Point,a photo showed the discovery of peat deposit that was exposed at very low tide and carbon dated at 900 years old. Dr. Steadman encouraged audience members to focus on existing common species of birds that have survived both natural and human-induced impacts over the ages before they too are gone.
As he concluded,Dr. Steadman warned that temperature and sea level changes will continue into the future with the temperature continuing to get warmer and sea levels continuing to rise.