BRANTA — Ruben C. Fijn
Diet of Cape and Snow Petrels at Signy, South Orkney Islands, Antarctica
Institution: VU University Amsterdam, IMARES Wageningen UR, the Netherlands
Supervisors: Jan Andries van Franeker (IMARES Wageningen UR), Phil Trathan (British Antarctic Survey), Hans Cornelissen (VU University Amsterdam)
Details: MSc 2006 (Completed)
Address: Bureau Waardenburg bv., P.O. box 365, NL 4100 AJ Culemborg, the Netherlands (Jan 2013) Email
Subject Keywords: diet, foodweb, water-off-load, regurgitate, stomach content, Antarctic Krill Euphausia superba, Myctophid fish, Lanternfish Electrona antarctica, chick-feeding, self-provisioning, Antarctica, Signy, South Orkney Islands
Species Keywords: Cape Petrel Daption capense, Snow Petrel Pagodroma nivea
Abstract
Food web knowledge is a prerequisite for adequate resource management in the Antarctic ecosystem. Accurate dietary specifications for the major consumers within the Antarctic ecosystem are needed. Procellariid species are the most numerous avian species in Antarctica and account for 20% to 40% of the overall consumption by seabirds in the area. Diet composition of two important procellariids, Cape and Snow Petrels, was studied at Signy Island during the breeding season 2005-2006. Food samples were obtained by stomach flushing of both chick-feeding birds and self-provisioning birds. Original prey mass was reconstructed from identifiable remains in the stomach samples. Significantly different diet compositions were found between chick-feeding and self-provisioning Cape Petrels based on reconstructed weight (chick-feeders 39:61:0:0, fish:crustacean:squid:other; self-provisioning birds 28:65:7:1, F:C:S:O). By contrast, no significant differences were found between chick-feeding Snow Petrels (66:34:0:0, F:C:S:O) and self-provisioning birds (68:32:0:0, F:C:S:O). Dominant prey items were Antarctic Krill Euphausia superba and the myctophid fish Electrona antarctica. Compared with findings undertaken at other locations, Cape Petrels at Signy Island had higher dietary fractions of crustaceans. Similarly, this study shows higher fractions of krill and lower fractions of fish in Snow Petrels at Signy Island than at other locations. A reasonable explanation for the high crustacean fraction in both seabird species might be the local high abundance of Antarctic Krill. This emphasises that local differences in diets need to be taken into account in modelling studies. Also, fish is an abundant prey item in both species, showing that, even in a strongly krill-dominated region, fish may remain an important part of the diet of Antarctic petrel species. The differences in diet between chick-feeding and self-provisioning Cape Petrels also show the importance of studying both groups in overall dietary research.
Published Papers
Fijn, R.C., Van Franeker, J.A. & Trathan, P.N. 2012. Dietary variation of chick-feeding and self-provisioning Cape and Snow Petrels at Signy, South Orkney Islands, Antarctica. Marine Ornithology 40: 81-87.
Fijn, R.C., Van Franeker, J.A. & Trathan, P.N. In press (December 2012). Vomit or Flush? Diet analysis using samples from spontaneous regurgitates or the water-off-load technique. Seabird.
Fijn, R.C. & J.A. van Franeker. 2007. Diet of Cape Petrel (Daption capense) and Snow Petrel (Pagodroma nivea) at Signy, South Orkney Islands, Antarctica.
First Prize winning poster during the NWO Polar Symposium, 9 March 2007, Groningen, Nederland.