Holocene vertebrate assemblages provide the first evidence for the presence of the barn owl (Tytonidae, Tyto alba) on Socotra Island (Yemen)

We describe the vertebrate remains found in a Holocene deposit inside the Taiti Cave, Socotra Island (Yemen). The fossils were found in a sand dune occupying almost entirely the main cavity of the Cave, with some bones collected on the surface and the majority of them found under its surface, in particular below a tiny level of hardened sand, the latter probably related to a guano deposit. They were mostly isolated bones, but under the guano layer, some of them were aggregated and recognizable as belonging toowl pellets. The analysis of the vertebrate remains reveals a great prey diversity and, together with the location of the pellet accumulation and the almost perfect preservation of the remains, indicates that the deposit derived from a pellet accumulation made by Tyto alba. This hypothesis is corroborated by a Tyto alba beak fragment found in the Hoq cave, in a deposit of uncertain stratigraphic context. The data presented herein represent the first documented evidence of the presence of Tyto alba on Socotra Island and indicate the probable existence of a now extinct population of Tyto alba on the island during the Holocene, already extinct at the time of the first ornithological surveys during the XIX Century.