The diet of the Barn Owl was investigated in 13 localities in the Pisa province, Central Italy. In each locality the percentage of forest and cultivated land, and the linear development of roads and rivers were recorded. To estimate the prey availability, the small mammal communities in seven different localities within the same province were sampled during live trapping sessions. Barn Owls preyed mainly upon rodents (79.4% ) and insectivores (18.8%), while birds were eaten to a small degree (1.9%). The main prey taxon was Apodemus sp. (39.7%), followed by Microtus savii (26.1%). The relative frequencies of these two prey items were negatively correlated. Statistically significant differences in the mean prey weight in the thirteen localities were detected. The mean prey weight was positively associated with the wood surface and negatively with the area of cultivated fields. A positive relationship between prey diversity and cultivation was recorded. This indicates that Barn Owls which forage in cultivated habitats tend to prey on smaller species, mainly shrews and voles, and to have a more diversified prey spectrum. On the contrary, owls foraging in wooded areas were more specialized and preyed on larger animals.
REFERENCES
G. Amori
,
M. Cristaldi
,
L. Contoli
1986. [On rodents (Gliridae, Arvicolidae, Muridae) of Italian peninsula and islands in relation to the bioclimatic Mediterranean environment]. Animalia 11: 217–269. Google Scholar
R. Brown
,
J. Ferguson
,
M. Lawrence
,
D. Lees
1987. Tracks and signs of the birds of Britain and Europe. Christopher Helm, London. Google Scholar
D. Capizzi
2000. Diet shifts of the Tawny owl Strix aluco in Central and Northern Italy. It. J. Zool. 67: 73–79. Google Scholar
D. Capizzi
,
L. Luiselli
1996a. Feeding relationships and competitive interactions between phylogenetically unrelated predators (owls and snakes). Acta Oecol. 17: 265–284. Google Scholar
D. Capizzi
,
L. Luiselli
1996b. Ecological relationships between small mammals and age of coppice in an oak-mixed forest in central Italy. Rev. Ecol. (Terre et Vie) 51: 277–291. Google Scholar
D. Capizzi
,
L. Luiselli
,
1998. Trophic niche relationships among coexisting Asio otus, Strix aluco and Tyto alba in central Italy. Rev. Ecol. (Terre et Vie) 53: 367–385. Google Scholar
L. Caroli
,
D. Capizzi
,
L. Luiselli
2000. Reproductive strategies and life-history traits of the Savi's Pine Vole, Microtus savii.
Zool. Sci. 17: 209–216. Google Scholar
J. Challine
,
H. Beaudvin
,
D. Jammot
,
M. C. Saint Girons
1974. [The prey of raptors]. Doin, Paris. Google Scholar
L. Contoli
,
F. Agostini
,
G. Aloise
,
A. Testa
1983. [On the relationship between terrestrial small mammals and the Barn Owl (Tyto alba Scopoli)]. Accademia Nazionale dei Lincei, Quaderni 256: 183–288. Google Scholar
L. Contoli
,
B. Ragonese
,
G. Areà
1993. [On the role of mammals in the diet of Tyto alba in the Ibleus sector (S-E Sicily)]. Atti e Memorie dell'Ente Fauna Siciliana 1: 59–78. Google Scholar
L. Contoli
,
G. Sammuri
1978. Predation on small mammals by Tawny Owl and comparison with Barn owl in the Farma valley (central Italy). Boll. Zool. 45: 323–335. Google Scholar
S. Cramp
(ed.). 1985. The birds of the Western Palearctic Vol. IV Oxford University Press. Google Scholar
G. Erome
,
S. Aulagnier
1982. Contribution a l'identification des proyes des rapaces. Bièvre, C.O.R.A., Université Lyon 4: 129–135. Google Scholar
D. E. Glue
1974. Food of the Barn owl in Britain and Ireland. Bird Study 21: 200–210. Google Scholar
L. Hansson
1967. Index line catches as a basis of population studies on small mammals. Oikos 18: 261–276. Google Scholar
C. M. Herrera
1974. Trophic diversity of the Barn owl Tyto alba in continental Western Europe. Ornis Scand. 7: 181–191. Google Scholar
W. Jędrzejewski
,
B. Jędrzejewska
,
A. Szymura
,
K. Zub
1996. Tawny Owl (Strix aluco) predation in a pristine deciduous forest (Białowieza National Park, Poland). J. Anim. Ecol. 65: 105–120. Google Scholar
Boulengé E. Le
,
P. Y. Le Boulengé-Nguyen
1987. A cost-efficient live trap for small mammals. Acta Theriol. 32: 140–144. Google Scholar
L. M. Lekunze
,
A. U. Ezealor
,
T. Aken'ova
2001. Prey groups in the pellets of the barn owl Tyto alba (Scopoli) in the Nigerian savanna. African Journal of Ecology 39: 24–32. Google Scholar
S. Lovari
,
A. Renzoni
,
R. Fondi
1976. The predatory habits of the Barn Owl (Tyto alba) in relation to the vegetation cover. Boll. Zool. 43: 173–191. Google Scholar
J. S. Marks
,
C. D. Marti
1984. Feeding ecology of sympatric Barn Owls and Long-eared Owls in Idaho. Ornis Scand. 15: 135–143. Google Scholar
B. Massa
,
M. Sarì
1982. [Comparing diet of Barn owl (Tyto alba Scopoli) in forest, rural and suburban habitats of Sicily (Aves, Strigiformes)]. Naturalista Siciliano 4: 3–15. Google Scholar
M. J. Norusis
1993. SPSS for Windows — User's Guide Release 6.0. SPSS Inc., Chicago. Google Scholar
E. B. Reed
1957. Mammal remains in pellets of Colorado Barn Owls. J. Mammal. 38: 135–136. Google Scholar
F. Riga
,
D. Capizzi
1999. Dietary habits of the Long-eared Owl Asio otus in the Italian peninsula. Acta Ornithol. 34: 457–51. Google Scholar
Girons M. C. Saint
1973. L'ages des micromammifères dans le régime de deux rapaces nocturnes, Tyto alba and Asio otus.
Mammalia 37: 439–456. Google Scholar
L. Santini
1983. [Italian rodents of agricultural and forest importance]. C.N.R., Padova, Italy. Google Scholar
M. Silva
,
J. A. Downing
1995. CRC handbook of mammalian body masses. CRC Press, Boca Raton, Florida. Google Scholar
R. R. Sokal,
F. J. Rohlf
1969. Biometry: the principles and practice of statistics in biological research. W. H. Freeman and Co., New York. Google Scholar
I. Taylor
1994. Barn owls — Predator-prey relationships and conservation. Cambridge University Press, Cambridge. Google Scholar
J. M. Thiollay
1968. Le régime alimentaère des nos rapaces: quelques analyses francaises. Nos Oiseaux 29: 249–269. Google Scholar
O. Uttendorfer
1952. Neue Ergebnisse uber die Ernahrung der Gerifvogel und Eulen. Verlag Eugen Ulmer, Stuttgart. Google Scholar
A. Zalewski
1996. Choiche of age classes of bank voles Clethrionomys glareolus by pine marten Martes martes and tawny owl Strix aluco in Białowieża National Park. Acta Oecol. 17: 233–244. Google Scholar
