Diet shifts of the tawny owl Strix aluco in central and northern Italy

Abstract

Feeding of tawny owl, Strix aluco, was studied from 14 localities of northern and central Italy, where it preyed mainly upon mammals and birds, but amphibians and invertebrates were also frequently eaten. Predation upon mammals was more important from autumn to spring, when alternative prey (amphibians, birds and invertebrates) were less available. The food niche overlaps, the linear distances (in km) between the various localities were negatively correlated, and the mean size of prey taken increased with the proportion of forested territory. However, where tawny owl preyed upon large forest mammals, it also preyed upon larger mammals not typical of forests. Considering the relationships between forest structure and tawny owl diet, it was found that forest density was positively correlated with the proportion of arvicolids and negatively with prey size diversity and the proportion of myoxids. The amount of forest territory within 1 km radius from each pellet collection site largely explained diet variability. Results of discriminant analysis, in addition, suggested that tawny owl is likely to avoid thick Mediterranean coppice forests as hunting habitats.

Barn OwlTyto albaPredation on Small Mammals in Relation to the Mediterranean Environment (Pisa Province, Italy)

“…Smaller prey seems to be chosen in open habitats, but more frequently ignored in the woods. The same trend was noted for the Tawny Owl throughout the Italian Peninsula (Capizzi 2000). Furthermore, we recorded a positive relationship between prey diversity and cultivated fields, but diversity values of small mammal assemblages recorded by live trapping were higher in the woodlands.…”

“…Birds, reptiles, amphibians and insects are only occasionally preyed. The high proportion of shrews in its diet suggests that this species is a non-selective small mammal predator, especially if compared with the Long-eared Owl Asio otus and the Tawny Owl Strix aluco (Mikkola 1983, Riga & Capizzi 1999, Capizzi 2000. In addition, these species are known to be selective towards age and sex classes of its small mammal prey (Saint Girons 1973, Jędrzejewski et al 1996, Zalewski 1996.…”

Helminth Communities of Owls (Strigiformes) Indicate Strong Biological and Ecological Differences from Birds of Prey (Accipitriformes and Falconiformes) in Southern Italy

“…However, each owl species can adjust their diet according to local availability, including a variable portion of birds, reptiles, amphibians and invertebrates [39], [42], [43]. Unfortunately no studies on feeding ecology of owls were available from Calabria, but results from studies in other regions of Italy largely conform to the general pattern described above, with scops owls feeding mainly on insects (orthopterans and moths) [44], barn owls, tawny owls and long-eared owls feeding more on small mammals [45], [46], [47], and little owls having a mixed diet of insects and small vertebrates [48].…”

Adaptive details in the comparison of predatory behaviourw of four owl species

“…In fact, both tawny and long-eared owls are moderately specialised to hunt small mammals, even in environments such as Italy where invertebrates are abundant (Malavasi, 1995;Capizzi, 2000). Consequently, they targeted the strikes to the mouse's head, similar to some Falconiformes species (Csermely et al, 1991(Csermely et al, , 1998Csermely, 1994).…”