Frequency of occurrence and ingested biomass of different prey of the barn owl Tyto alba in an island ecosystem

The Barn Owl Tyto alba is commonly reported as a non-selective predator of small mammals,and its diet has been thoroughly analyzed also to assess the small mammal assembly composition inmany study areas. The aim of this work was to analyze the diet of the Barn Owl in the Elba islandthrough the analysis of 161 pellets collected in September 2020. Undigested fragments were isolatedand compared with reference collections. We confirmed that the Barn Owl is a typical predator offield mice (62% of relative frequency), with synanthropic murid rodents as the second category ofprey. The frequency of consumption of shrews increased by 9% with respect to the previous work,suggesting that the natural environment of Elba island is still in a good health status. Moreover,fragments of two newborn hares were detected, increasing the knowledge on the local trophicspectrum of the Barn Owl. Finally, the skull of a Georoy's Myotis Myotis emarginatus confirmed thepresence of this species in Elba island after over 60 years from the first unconfirmed record. Repeatedstudies conducted in the same study site may provide useful information on prey population trendsand local environmental status.