David Wingate
From the late 1950s through the ’70s, I conducted extensive searches for fossil bird bones in Bermuda’s caves, and other sites, with the goal of describing Bermuda’s pre-colonial avifauna in greater detail. While most of the bones were found as loose deposits of recent (Holocene) origin on the floors of caves and represented species like the Cahow, Audubon’s Shearwater and small owl, which were reported by the first settlers, a few older deposits exposed by blasting in the government quarry in 1960, hinted at a much more diverse avifauna in the early Pleistocene, including a flightless crane, a flightless duck and several species of marsh birds in the rail family.
Of particular interest in the government quarry was a beach rock deposit extending to seventy feet above present day sea-level. A similar aged beach rock on the Castle Harbour Islands contained the bones of adult and nestling short-tailed albatross, confirming that the species once nested in Bermuda, even though albatrosses were not previously known in the North Atlantic later than the Pliocene.
Concurrent geological research on the age of Bermuda’s carbonate rocks and their deposition in relation to the sea-level fluctuations of the Ice Age (which is being carried out by Hearty, Vacher, Pascal and other geologists worldwide), has revealed that this high sea stand occurred at the end of the interglacial period known in Bermuda as the ‘Upper Town Hill Formation’. The recent get-together of Storrs Olson, from the Smithsonian (who is describing the pre-colonial avifauna in collaboration with me), and geologist Paul T. Hearty, who has been documenting evidence for the same seventy-foot high inter-glacial sea stand in the Bahamas, brings our work to the final stage of correlating the geology with the different ages of the bird bone deposits. Sophisticated dating techniques now confirm that the
high sea stand occurred 400,000 years ago, plus or minus 30,000. It is our conclusion that this drowning of most of Bermuda at that time was the main cause of extinction for the more diverse early Pleistocen avifauna.
