Spatial and temporal taphonomic study of bone accumulations of the burrowing owl (Athene cunicularia) in central Argentina

Abstract

Athene cunicularia is a very common opportunistic raptor inhabiting diverse environments of South America. It has variable hunting behavior and diet habits, feeding mostly on arthropods and nocturnal and diurnal micromammals. We evaluated taphonomically mammal bones accumulated in pellet samples produced by this raptor recovered from different areas of Central Argentina. The sum of the observed taphonomic attributes on digested skeletal elements (digestion, relative abundance, indexes, and breakage) allow assigning this species to the category of moderate modification, but with several attributes located in a different category with respect to previous classification. This difference may be linked with the representation and estimated body mass of prey; when the sample has larger prey (e.g. caviomorph rodents), there is a higher degree of modification. Results of this evaluation were used for comparison with paleontological and archaeological sites in Argentina, where this owl was indicated as one of the possible accumulator agents. We propose that only large fossil samples allow a good evaluation of taxonomic diversity and therefore of the prey body mass representation. Here, we applied a new categorization of rodent skull breakage. Finally, this evaluation of modern samples leads to the incorporation of molariforms of Octodontidae (Rodentia) and teeth of Chiroptera in the categories of modifications by digestion.