Linking foraging behavior and diet in a diving seabird

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

MARINE ECOLOGY-PUBBLICAZIONI DELLA STAZIONE ZOOLOGICA DI NAPOLI I

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2015

0173-9565

Foraging behavior and diet of breedingseabirds may be analysed simultaneously with the combined use of remote sensingdevices and stable isotope analysis. Imperial shag, Phalacrocorax atriceps, breeding at Punta Le_on colony, Argentina, were equipped with globalpositioning system (GPS) loggers to record foraging trips and blood sampleswere taken after removal of the devices in order to analyse their nitrogen andcarbon stable isotope composition in whole blood and plasma. Whole blood wascorrelated to plasma isotopic composition for each individual (n = 35), linking diet in the short and medium term.Sexes did not differ in isotopic signatures. The maximum distance reached andthe total number of dives that individuals made on two consecutive foragingtrips were correlated to their plasma nitrogen isotopic signature. Individualsthat went further from the colony and dived fewer times presented more positivesignatures, indicative of benthic prey consumption (e.g. Raneya brasiliensis). Diet was predominantly benthic withsome individuals incorporating pelagic 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 individuals weresimilar to those of the same species in other colonies further south along thePatagonian coast.