@misc{Riga_Francesco_Dietary_1999,
 author={Riga, Francesco and Capizzi, Dario (1967– )},
 editor={Polska Akademia Nauk. Muzeum i Instytut Zoologii},
 copyright={Rights Reserved - Restricted Access},
 address={Warszawa},
 howpublished={online},
 year={1999},
 language={eng},
 language={pol},
 abstract={Feeding habits of the Long-eared Owl in the Italian peninsula were investigated by using mainly data from bibliographic sources. A total of 4651 prey items from 13 study localities were used in the analysis. Field voles Microtus sp., which globally accounted for over 51.4% of the cumulative total, were the most important prey, followed by the mice Apodemus sp. (31.5%). Insectivores (6.0%) and birds (4.7%) were preyed less frequently. In order to represent the diet of Long-eared Owls some dietary parameters were computed, such as percentages of occurrence of the most important prey taxa (insectivores, murids, arvicolids, and birds), mean prey size, taxonomic diversity and prey size diversity. The linear relationships between the variables were assessed by using either Spearman-rank and Pearson correlation coefficients. Taxonomic dietary diversity was positively correlated with site latitude. Geographic linear distances (in km) of the various study sites and relative niche overlap values were negatively correlated. The dietary diversity was positively correlated with the proportion of murids and negatively with arvicolids. It suggests that the Long-eared Owl is quite specialised in feeding upon arvicolids when the availability of this prey is high. Furthermore, one-way ANOVA revealed that significant differences in mean prey size between the different localities were present. Performing a Principal Component Analysis on the dietary parameters we observed a separation of the study sites in two different groups along the first factor, and the proportions of arvicolids and murids were the most important parameters in order to explain the observed variability.},
 type={Text},
 title={Dietary habits of the long-eared owl Asio otus in the Italian peninsula},
 volume={34},
 number={1},
 journal={Acta Ornithologica},
 publisher={Muzeum i Instytut Zoologii PAN},
 keywords={Long-eared Owl, behaviour, nutrition, Italy, small mammals, trophic ecology, birds, typical owls, true owls, Asio otus, Strigidae, Aves},
}