HOW IMPORTANT ARE PELAGIC PREYS FOR THE KELP GULL DURING CHICK-REARING AT THE SOUTH SHETLAND ISLANDS

An analysis of pellets regurgitated indicated adult kelp gulls (Larus dominicanus) on the South Shetland Islands consumed predominantly inte rtidal prey, whereas previous studies at Antarctic Peninsula sites hav e reported kelp gulls consuming predominantly pelagic species. The pel lets collected at Nelson Island during the chick-rearing period indica ted that the limpet Nacella concinna was their most frequent prey, fol lowed by carrion, gammariids, snails and krill. Fish were scarcely rep resented. Also, regurgitated stomach contents of chicks showed that li mpets and carrion were the most frequent food items, accounting for 70 % of the mass. However, gammariids were particularly important by numb er. Significant differences were observed in the overall comparison of the diet as reflected by the two sampling methods. In general, the im portance of pelagic prey was negligible when compared to intertidal or scavenged prey. Our results differ greatly from those reported for th e Antarctic Peninsula, where chicks were almost exclusively fed with t he pelagic fish Pleuragramma antarcticum. These differences could be r elated to the abundance of pelagic resources in southernmost latitudes , and/or to the presence of more extensive intertidal foraging areas a t the South Shetland Islands.