Over-representation of bird prey in pellets of South Polar Skuas

• Published in: Journal of Ornithology
• Main Authors: Santos, Maria Mercedes, Juares, Mariana Alejandra, Rombola, Emilce Florencia, Garcia, Mirta Lidia, Coria, Néstor Rubén, Doncaster, C. Patrick
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer
• Subjects: ANTARCTICA; DIETARY ANALYSIS; PELLET ANALYSIS; REGURGITATE ANALYSIS; SYMPATRIC; https://purl.org/becyt/ford/1.6; https://purl.org/becyt/ford/1; Antarctic; The Antarctic; Antarctic Peninsula; Argentino; Argentina; Cierva; Potter Peninsula; Cierva Point; Lidia; Antarc*; Antarctica; antarcticus; Dirección Nacional del Antártico; Instituto Antártico Argentino; South Polar Skuas; Stercorarius antarcticus; Stercorarius maccormicki
• Online Access: http://hdl.handle.net/11336/196779

We report the first study to compare the contents of pellets and regurgitates of South Polar Skuas, Stercorarius maccormicki, at two breeding colonies on the Antarctic Peninsula. Samples were taken across years from identified breeding pairs at Potter Peninsula in sympatry with 30-40 breeding pairs of Brown Skuas, Stercorarius antarcticus lonnbergi, and from Cierva Point with 2 pairs of Brown Skuas. In contrast to the general consensus that penguins feature in the diet most prominently in the absence of Brown Skuas, we found a much more frequent occurrence of penguin remains in samples at Potter than Cierva, but only in pellets. At Cierva, penguin feathers were largely replaced in the pellets by a high frequency of non-food moss. The rare occurrence of penguins in regurgitates from both sites is consistent with scavenging rather than active predation. The high frequency of feathers in pellets at Potter is consistent with a gut-cleansing function similar to that performed by moss, which is abundant only at Cierva. We conclude that pellets over-represent penguins in the diet. For any species that consumes feathers, the evidence must consider the alternative possibility of a nonfood function of ingesting feathers. Fil: Santos, Maria Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina Fil: Juares, Mariana Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina Fil: Rombola, Emilce Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina Fil: Garcia, Mirta Lidia. Consejo Nacional de Investigaciones Científicas y Técnicas; ...