PELLETS AND PREY REMAINS AS INDICATORS OF THE DIET OF TWO SYMPATRIC SKUAS (AVES: STERCORARIIDAE) ON KING GEORGE ISLAND, ANTARCTICA

South Polar skua (Stercorarius maccormicki) and Brown skua (Stercorarius antarcticus lonnbergi) have opportunistic feeding habits and are the dominant predators in terrestrial Polar regions. These skuas exploit a wide range of food items, including marine organisms, other birds, and even garbage. In the present study, we compare the diets of these two skua species during the breeding season, using pellets and prey remains collected within their territories. The samples were collected at six sites in Admiralty Bay, on King George Island, Antarctica. We identified eight different items, which we classified as “penguin”, “flying bird”, “skua”, “fish”, “gastropod”, “krill”, “egg” and “marine debris”. In the first breeding season (2008/2009), penguins and flying birds were the food resources more abundant for both skua species, and their diet composition was similar. In the second breeding season (2010/2011) South Polar skua exploited more fish and flying birds than Brown skua; the latter exploited more eggs and penguins. Our findings corroborate those of previous studies, demonstrating that in sympatry South Polar skua exploit more fish than Brown skua. The diet of South Polar skua also varied between breeding seasons, reflecting the opportunistic foraging behavior of these skuas. As in other studies, we recorded that skua is a food resource for both skua species, but it was more common in the diet of South Polar skua. Marine debris was recorded only in the samples of Brown skua. Birds are important food items for both skuas, although significant differences were found in the diets of these sympatric species, with shifts in the composition of the diet probably reflecting fluctuations in the abundance of prey populations, which are known to be common at Admiralty Bay, although more data will be needed to confirm this link.

Penguins Strike Back: A Report on the Unusual Case of Adélie Penguin (Pygoscelis adeliae) Attacks on South Polar Skua Nests Distant from the Breeding Colony

Colonial seabirds use various methods to defend their nests from predators [...]

Past records and current distribution of seabirds at Larsemann Hills and Schirmacher Oasis, east Antarctica

Seabird populations in Antarctica serve as indicators to assess the impacts of global environmental change. Ecological data on seabirds in Antarctica are scarce due to limited knowledge on their distribution and abundance in most parts of the continent. In this study, we investigated the status of seabird species around the Indian research stations Bharati at Larsemann Hills, Prydz bay and Maitri at Schirmacher Oasis, central Dronning Maud Land located in east Antarctica. We conducted primary surveys during austral summers under the Indian Antarctic Program and compiled published as well as unpublished information on seabird distribution from these areas. We employed intensive area search methods to locate presence of seabird nesting and moulting sites. Ten species were recorded from Larsemann Hills with confirmed breeding of snow petrel, south polar skua and Wilson’s storm-petrel. Only south polar skua and Adélie penguin were reported breeding at Schirmacher Oasis with unconfirmed breeding of Wilson’s storm-petrel. This study presents the first detailed synthesis of status of seabirds from Larsemann Hills and Schirmacher Oasis regions in Antarctica and serves as a strong baseline for future ecological work on seabirds in the sector of operation of Indian Antarctic Program.