Neotaphonomic Analysis of Bone Accumulation by a Nocturnal Raptor (Bubo bubo): Evidence From Avian Remains in Oliva Mountain (Tarragona, Spain)

Abstract

Raptors play a major role in the formation of avian bone assemblages. To distinguish the agents responsible for accumulations, it is necessary to deepen their taphonomic patterns, derived from the consumption process carried out by the predator. These patterns aid in interpreting fossil assemblages, facilitating palaeoecological reconstruction and the analysis of predator–prey interactions. In turn, different nocturnal raptor species exhibit highly variable consumption and accumulation patterns, whereas even the same species can generate distinct signatures. Consequently, avian accumulations from the same raptor species may vary in prey taxonomy, anatomical representation, and bone surface modifications. Neotaphonomy plays a crucial role in analyzing these patterns in modern bone assemblages, where the predator is known. We analyzed three avian assemblages from different areas of Oliva Mountain (Tarragona, Spain), where the Eurasian eagle-owl (Bubo bubo) foraged for 1 year, revealing different consumption patterns within the same ecological niche. Most remains were accumulated during the breeding season; however, the observed patterns suggest the predator mainly used this area for roosting. Differences in functionality—plucking, dismemberment, and regurgitation—of the analyzed assemblages according to prey consumption stages by B. bubo have been identified. The consumed prey primarily belong to Columbiformes and Passeriformes, exhibiting variability in anatomical representation, beak modifications, and digestion damage across the studied areas. In the case of Columbiformes, greater peck damage on the scapular joints suggests wing detachment to facilitate consumption by B. bubo. On the other hand, Passeriformes exhibited fewer beak marks but higher digestion rates, likely due to full ingestion. In this study, we provide a new neotaphonomic perspective on the accumulations generated by a nocturnal raptor such as B. bubo, documenting its ability to produce different avian assemblages depending on the stage of prey consumption. This enables the characterization of distinct prey consumption and accumulation patterns by a specific species, which allows for the recognition of these patterns in fossil assemblages and the identification of potential accumulating agents.