Foraging behaviour of Magellanic Penguins during the early chick-rearing period at Isla de los Estados, Argentina

ROSCIANO, NATALIA G.; PÜTZ, KLEMENS; POLITO, MICHAEL J.; RAYA REY, ANDREA

IBIS

WILEY-BLACKWELL PUBLISHING, INC

Año: 2018 vol. 160 p. 327 - 341

0019-1019

tudies of the at-sea distribution and trophic ecology of penguins are essential to understandtheir role in the broader marine food web. Magellanic Penguins Spheniscus magellanicushave a wide distribution and their foraging behaviour varies across breeding sites andbetween sexes, among others. In this study, we characterized the at-sea areas, the divingstrategies and the relative trophic level of Magellanic Penguins breeding at Isla de los Estados,Argentina, during the early chick-rearing period. In addition, we quantified the interannual,sexual and individual variability in those parameters during three breeding seasons(2011?2013) using devices recording position and dive depth, and obtained blood samplesfor stable isotope analysis. During the early chick-rearing period, Magellanic Penguinsshowed small differences between the sexes in their foraging behaviour and large overlapin the at-sea areas used, suggesting no intraspecific variation between sexes. Althoughthere was interannual variability in the foraging behaviour and the trophic level of thepenguins, most of the studied nests managed successfully to raise both chicks during thefirst stage of the breeding cycle (guard stage). The foraging ecology of Magellanic Penguinsfrom this colony was comparable with results of past studies at other breeding colonies.This study contributes to the identification of important at-sea areas for MagellanicPenguins at the southern edge of their distribution and also to the identification of possiblethreats in the study area such as interaction with fisheries.