Impact of predation by the black rat, rattus rattus, on the breeding success of cory’s shearwater, Calonectris diomedea, on Linosa island (Sicily, Italy)

Black Rat, Rattus rattus, is one of the most common species on Mediterranean islands; it is found on all of the large and medium-sized islands, and on many of the smallest ones as well (Perfetti et alii, 2001). On Linosa, the Black Rat was introduced by man and its density is not evaluable at present. Linosa island hosts the largest breeding colony of Cory’s Shearwater, Calonectris diomedea, in Italy (estimated at 10.000-15.000 pairs, Iapichino & Massa, 1989), and the second largest colony in the west-central Mediterranean (Granadeiro et alii, 1997). The aim of this work was to verify for the first time the limiting factors influencing breeding success in the Cory’s Shearwater breeding colony on the island of Linosa, with special attention to the impact of Black Rats.