Abstract :
We review and update available information on the population size and distribution of Cory’s Shearwater, Calonectris diomedea, and Yelkouan Shearwater, Puffinus yelkouan, in Italy. More than 90% of the population of these species rely on 64 islands, but the former breeds on twice as many islands as the latter. Some cases of local extinction were recorded. The analysis of distributions, along with that of island featu-res and presence of rats, showed inter-specific differences. The Yelkouan Shearwater tends to occupy larger and more offshore islands than the other species does. It’s the only one that shows a clear positive correlation between abundance and island size. Finally, it is not present in rat-free islands, with a single exception of no quantitative relevance. Available data on the breeding success of both species are presented; comple-te failures where rats occur were recorded. Operations of rat control or eradication are presented and their consequences on seabirds’ breeding success commented.
