The importance of fish in the diet of the South Polar Skua (Stercorarius maccormicki) at the South Shetland Islands, Antarctica

Diet of South Polar Skua Chicks in Two Areas of Sympatry with Brown Skua

“…No dehydration was observed in adult Brown Skuas, since electrolyte levels were similar to those described for South Polar Skuas (Rosa et al 1993). Multiple blood metabolites (lipids, proteins and glucose) are regulated by dietary intake and metabolism and serve as an indicator of the nutritional status of wild (Reinhardt and Van Vleet 1986;Reinhardt et al 1997;Montalti et al 2009). In Antarctic skuas, glucose values were similar between adults, while age-related differences (higher in adults) were observed.…”

“…In particular, Brown Skua (Stercorarius antarcticus) and South Polar Skua (S. maccormicki) (hereafter Antarctic skuas) are top predators that nest in subantarctic islands and the Antarctic (Ritz et al 2006(Ritz et al , 2008. When breeding in sympatry, Brown Skuas monopolize the terrestrial feeding resources (i.e., penguin colonies) while South Polar Skuas feed at sea (i.e., fish) (Montalti et al 2009;Graña Grilli and Montalti 2014). The skuas that feed at sea have wider home ranges and take longer feeding trips, leaving their nests unattended for longer periods than those feeding on terrestrial resources and searching for food near their nests (Graña Grilli et al 2011).…”

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

“…All studies using regurgitates and direct observations from areas in sympatry with Brown Skuas report a predominance of fish in the diet (Trivelpiece et al 1980;Pietz 1987;Reinhardt 1998;Montalti et al 2009;this study). Pellet studies in contrast also report a substantial (20-89 %) contribution from penguins, both in sympatry (Peter et al 1990;Graña Grilli and Montalti 2011;this study) and in allopatry (e.g.…”

“…South Polar Skuas (Stercorarius maccormicki), which are amongst the most southerly distributed of all seabirds, feed by predation, scavenging and kleptoparasitism (Young 1994), making them efficient opportunists in the harsh Antarctic environment. In areas of sympatry with Brown Skuas (Stercorarius antarcticus lonnbergi), South Polar Skuas are reportedly almost wholly piscivorous (amongst many : Pietz 1987;Reinhardt 1997Reinhardt , 1998Reinhardt et al 2000;Hahn et al 2008;Montalti et al 2009). In allopatry, they reportedly feed largely on penguins and fish (Young 1963(Young , 1994Müller-Schwarze 1973, 1977;de Brooke et al 1999;Baker and Barbraud 2001;Pezzo et al 2001).…”

Injuries of Webs on the Feet of South Polar Skuas <i>Catharacta Maccormicki</i>: Results of Studying Active Obliged Aggregations

“…These opportunistic generalist predators use scavenging, predation, and kleptoparasitism as their main strategies to procure food [14][15][16][17], rarely cannibalism [18]. The exact composition of the diet and feeding strategies are highly variable among different locations [for example, [19][20][21][22].…”