The winter distribution of Adélie and chinstrap penguins from two breeding colonies in the South Shetland Islands of Antarctica

Satellite telemetry was used to determine the winter movements and distributions of five chinstrap and six Adélie penguins from two breeding colonies in the South Shetland Islands, Antarctic Peninsula region during the 2000 and 2001-2002 austral winters, respectively. Three chinstrap penguins from a breeding site in Admiralty Bay, King George Island (62° 10’ S, 58° 30’ W) were instrumented with satellite tags in early March 2000, following their annual molt; similarly, two birds were tagged in late February at their breeding site on Cape Shirreff, Livingston Island (62° 28’ S, 60° 46’ W). All five chinstrap penguins were tracked for a minimum of three months each, while one bird was followed for 5 months. Locations were obtained using the ARGOS satellite system and data analyses revealed that 4 of the 5 chinstrap penguins foraged largely on the shelf to the north and northeast of the South Shetland Islands in ice-free areas. The fifth chinstrap penguin, from the colony on KGI, proceeded northeast to the Elephant Island area and spent the next 4-5 months continuing to the East. This bird’s signal was lost just to the west of the South Sandwich Island group in late July, approximately 1300 km from its breeding colony. The migration path of this chinstrap penguin is remarkably similar to the only other record of a chinstrap penguin’s winter migration reported by Wilson et al. (1998). Three Adélie penguins with PTTs were tracked from mid-February to early April 2001, following their molt in the KGI breeding colony. All individuals remained in the Bransfield Strait adjacent to the western shore of the Antarctic Peninsula, within 150 km of the breeding colony where they were tagged. The following season, we attached PTTs to three Adélie penguins feeding large, nearly fledged chicks on KGI in late January 2002. We tracked all three around the tip of the Antarctic Peninsula, deep into the Weddell Sea where they presumably hauled out to molt in late March – early April, between 69° and 70° S latitude. Our results suggest that Adélie and chinstrap penguins breeding in the same colonies during the summer may have vastly different migratory behaviors in winter. This may be a strategy evolved to avoid significant losses to any given breeding population by dispersing individuals to different winter ranges.