Pellets as indicators of diet in Antarctic Skuas (Catharacta spp.) at Admiralty Bay, King George Island (Antarctic Peninsula)

Apresentado originalmente no: SCAR Open Science Conference, Buenos-Aires, 3-6 August 2010.

Ana Olivia de Almeida Reis, Erli Schneider Costa & Maria Alice dos Santos Alves. 

Abstract: Skuas are opportunistic predators and scavengers seabirds. They occupy the top of food chain in Antarctic region. Several seabirds regurgitate indigestible prey remains in discrete pellets that could supply wide data about diet. In the present study we used pellets of breeding skuas (Catharacta spp.) at Keller Peninsula and Hennequin Point (Admiralty Bay) to determine the main components of their diet.  The pellets were collected by Costa during the breeding period of 2008/2009. We analyzed  33 samples at the Laboratório de Ecologia de Aves of Universidade do Estado do Rio de Janeiro (UERJ) and categorized them in different food items, in accordance of the lowest possible taxon of the prey. The mainly item recorded was adult penguin feathers that were found in 81.82% of all the pellets analyzed (n=33). We also recorded evidence of fish (in 57.57% of pellets), unidentified birds (48.48%), Wilson's Storm-petrel - Oceanites oceanicus (18.18%), Nacella concinna shells (12.12%), Antarctic tern - Sterna vittata (9.09%), and egg’s fragments (3.03%). The preliminary results indicate that a substantial part of skuas´ diet is other seabirds and their impact on globally important species for conservation requires further monitoring and analysis. (This work was supported by The National Council for Scientific and Technological Development (CNPq), Brazilian Antarctic Program (PROANTAR) (CNPq/PROANTAR 550040/2007-2 and CNPq/MCT 557049/2009-1). ESC received a CNPq fellowship (141474/2008-4), and MASA received a CNPq grant (3027185/03-6).

Clique aqui para baixar o poster.