Nest attendance of Southern Giant Petrel (Macronectes giganteus) on Elephant Island

Abstract

According to expressive size dimorphism between Southern Giant Petrel genders, differences in foraging and nest attendance are expected between female and male petrels. This study aims to investigate differences in nest attendance duration and frequency. 14 Adults were tagged with radio-transmitters, seven females and seven males, of which five were breeding pairs, in Stinker Point, Elephant Island. The radio signals were registered by an Automatic Listening Station between December 2009 and February 2010. Females attend more often the nest than males (binominal test, Chi2 = 799.3; P < 0.001), although the mean number of days each gender attended the nest was not different (F = 0.01; P = 0.92). Our results suggest a higher breeding effort in females while larger males may trade off reproduction success in favor of own survival, at least in anomalous summers. Under severe climatic conditions like the austral summer of 2009/2011 males tend to abandon the nest earlier than females.