PRESERVATION POTENTIAL OF OWL DERIVED VERTEBRATE REMAINS FROM SAN SALVADOR ISLAND, THE BAHAMAS

Within the past decade, there has been an increase in taphonomic studies of owl pellets and their role in the formation of Tertiary microvertebrate assemblages. In this study, I document the formation of cave bone accumulations produced primarily by the predatory activity of barn owls. The project augments previous studies, which were primarily focused on clastic settings in temperate climate, by exploring taphonomy of owl pellets in karst-dominated, carbonate subtropical setting on a small oceanic island. The study was conducted on San Salvador Island (The Bahamas), a small subtropical carbonate island with numerous pit caves. Previous studies mentioned a resident barn owl, Tyto alba, which had taken roost in a pit cave on the island, known locally as “Owl’s Hole”. The cave, which appeared to be still actively occupied by one or more owls in July 2017, provided a suitable opportunity to examine owl pellet taphonomy and resulting cave accumulations of microvertebrate bone remains. Located on the southwestern end of the island, in what is known as the “Sandy Point Pits”, “Owl’s Hole” is the largest of a series of pit caves documented in the area. In this study, “Owl’s Hole” was divided into four horizons. Each horizon representing a specific cave level at which bone material accumulated, starting at the roost and ending at the base of the cave. Samples were collected at each horizon and wet sieved using a 2.3 mm mesh. Bone material was then separated, identified, and categorized based on a series of taphonomic and anatomical parameters. Preliminary results suggest a general trend towards the deposition of primarily mammalian bone material. An increase in fracturing with depth, as well as an increase in diagenetic alteration was also noted. In this paper I discuss the effects of fluvial transport in an environment with a relatively steep incline, and any potential structural and/or diagenetic alteration of bones caused by various factors (i.e. relative climate, burial depth, length of exposure). How these factors affect preservation should provide insight into what may contribute to the potential bias of small vertebrate remains found in an owl derived depositional environment. As a result, these findings are likely to assist in the understanding of true faunal assemblages present in specific paleoecological settings.