Aspects of the foraging behaviour of the Antarctic Tern Sterna vittata gaini at Harmony Point, South Shetland Islands.

CASAUX, R; BARONI, A.; RAMÓN, A.; FAVERO, M.; SILVA, P.

POLAR BIOLOGY

Springer-Verlag

Año: 2008 vol. 31 p. 327 - 331

0722-4060

Abstract During January and February 2002 and 2003 we studied the diet of the Antarctic Tern Sterna vittata gaini at two colonies located at Nelson Island, South Shetland Islands, by identifying the preys carried to the nest by breeders. The fish Notothenia coriiceps was the main prey in both seasons, followed by the Myctophid Electrona antarctica, the Antarctic krill Euphausia superba and gammaridean amphipods. The contribution of fish to the diet of chicks increased as they grow older. Fish and gammaridean amphipods were represented in the diet all day long, whereas Antarctic terns preyed on the Antarctic krill mainly during the sunrise and the sunset. Both, the duration of the feeding trips and the number of trips per foraging bout were determined by the type of prey caught. Preliminary information suggest that the foraging strategy is strongly influenced by the predation pressure on chicks. The results are compared with the only two previous studies on the diet of the Antarctic Tern carried out at the South Shetland Islands.