linking foraging behavior and diet in a diving seabird

SABRINA HARRIS; FLAVIO QUINTANA; JAVIER CIANCIO; LUCIANA RICCIALDELLI; ANDREA RAYA REY

MARINE ECOLOGY-PUBBLICAZIONI DELLA STAZIONE ZOOLOGICA DI NAPOLI I

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2015

0173-9565

Foraging behavior and diet of breeding seabirds may be analysed simultaneouslywith the combined use of remote sensing devices and stable isotope analysis.Imperial shag, Phalacrocorax atriceps, breeding at Punta Leon colony,Argentina, were equipped with global positioning system (GPS) loggers torecord foraging trips and blood samples were taken after removal of the devicesin order to analyse their nitrogen and carbon stable isotope composition inwhole blood and plasma. Whole blood was correlated to plasma isotopic compositionfor each individual (n = 35), linking diet in the short and mediumterm. Sexes did not differ in isotopic signatures. The maximum distancereached and the total number of dives that individuals made on two consecutiveforaging trips were correlated to their plasma nitrogen isotopic signature.Individuals that went further from the colony and dived fewer times presentedmore positive signatures, indicative of benthic prey consumption (e.g. Raneyabrasiliensis). Diet was predominantly benthic with some individuals incorporatingpelagic prey (Engraulis anchoita) and even cephalopods (Octopus tehuelchus).Within breeding pairs (n = 9), different combinations of foraging andprey preferences were observed. Estimated trophic levels of these individualswere similar to those of the same species in other colonies further south alongthe Patagonian coast.