(Table 1) Egg size, clutch asymmetry, hatch date and breeding success in south polar skua, brown skua and mixed pairs on King George Island ...

• Main Authors: Hahn, Steffen, Reinhardt, Klaus, Ritz, Markus S, Janicke, Tim, Montalti, Diego, Peter, Hans-Ulrich
• Format: Dataset
• Language: English
• Published: PANGAEA 2007
• Subjects: Time coverage; Species; Species, common name; Egg volume; Sample amount, subset; Eggs, clutch asymmetry; Comment; Date; Number of fledglings per nest; Biological sample; Calculated according to Catry & Furness 1997; Priority Programme 1158 Antarctic Research with Comparable Investigations in Arctic Sea Ice Areas SPP1158; Antarctic; Arctic; Furness; King George Island; Antarc*; Antarctica; Brown Skua; Catharacta maccormicki; Sea ice; South Polar Skuas; Stercorarius maccormicki
• Online Access: https://dx.doi.org/10.1594/pangaea.848021; https://doi.pangaea.de/10.1594/PANGAEA.848021

We studied how environmental conditions affect reproduction in sympatric skua species that differ in their reliance on marine resources: the exclusively marine foraging south polar skua Catharacta maccormicki, the terrestrially foraging brown skua C. antarctica lonnbergi and mixed species pairs with an intermediate diet. Egg size, clutch asymmetry and hatching dates varied between species and years without consistent patterns. In the south polar skuas, 12 to 38% of the variation in these parameters was explained by sea surface temperature, sea ice cover and local weather. In mixed species pairs and brown skuas, the influence of environmental factors on variation in clutch asymmetry and hatching date decreased to 10-29%, and no effect on egg size was found. Annual variation in offspring growth performance also differed between species with variable growth in chicks of south polar skuas and mixed species pairs, and almost uniform growth in brown skuas. Additionally, the dependency on oceanographic and climatic ... : Note that Catharacta maccormicki and Catharacta antarctica lonnbergi are more officially called Stercorarius maccormicki and Stercorarius lonnbergi.Total ranges for the parameters egg volume, clutch asymmetry and hatching date were:1. South polar skua: 64.7-107.7 cm**3; 0.760-1.159; 11 Dec-17 Feb2. Mixed species pairs:, 78.7-112.8 cm**3; 0.839-1.111; 5 Dec-29 Jan3. Brown skua: 77.9-123.7 cm**3; 0.873-1.105; 6 Dec-8 Feb ...