Factors affecting survival of fledgling Manx Shearwaters Puffinus puffinus

Abstract

During an 11-year period starting in the mid-1960s, large numbers of fledgling Manx Shearwaters Puffinus puffinus were ringed and recaptured on Skokholm Island, Pembrokeshire, Wales. Since it is unlikely that any more will ever be found, this paper summarises the factors that affected the chances of a fledgling surviving long enough to be recaptured on the island. Both the date on which they were ringed and their weight at that time influenced the probability that they would be recaptured. Some implications for the annual cycle are discussed.