Densità e biologia riproduttiva del grillaio  Falco naumanni nella piana di Gela (Sicilia)

Mascara R.,, Sarà M.

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Density and breeding biology of the lesser kestrel Falco naumanni in the Gela Plain (southern Sicily). The lesser kestrel Falco naumanni population of the Gela Plain (southern Sicily) has been monitored for three years (2003-2005) in a study area of 450 km2. The results were compared with those from two earlier censuses (1981 e 2001). In the study period, 48 colonies were recorded, 83.3% of them in rural houses, and the population reached 260 (range 233-287) pairs. The lesser kestrel in the Gela Plain was continuously increasing since 1981, when only 17-21 pairs were present in 7 colonies. During the 2004-2005, 135 nests were detected and 339 birds (330 nestlings and 9 adults) were ringed. The mean clutch, brood and fledgling sizes and productivity were among the highest so far recorded in the European species’ range. Nonetheless, in 2005, the 9.1% of colonies were destroyed by black rats Rattus rattus and the 7.8% by men. The area hosts nearly one-third of the whole Sicilian population and represents one of the most important Italian populations. Current land use, based on traditional cereal and semi-intensive farming, is the main reason for the observed population increase. The species avoids the coastal part of the study area due to industrial farming (green-houses) and urbanization. The planned agricultural turn-over under the auspices of the CAP, which includes the development of irrigation schemes and expansion of industrial farming toward inland, seriously threatens the whole Gela Plain and urges for the implementation of conservation measures.