Geolocation and stable isotopes indicate habitat segregation between sexes in Magellanic penguins during the winter dispersion

The Magellanic penguin (Spheniscus magellanicus) is a top predator and a major consumer of marine resources in the Patagonian Continental Shelf and worldwide. It is the most highly migratory of the Spheniscus penguins, but until recently, its migration route was only partially known. Regarding Magellanic penguins breeding on Isla Quiroga, in Argentina, our goals were: (1) to compare distribution during winter period between sexes and (2) if habitat is found to be segregated, to evaluate possible proximate causes like competitive exclusion and/or habitat specialization. In March 2017 and 2018, prior to migration, 26 penguins were equipped with MK3/4 geolocators, which were recovered in late September/early October. Penguins dispersed northwards as far as 29°S and southwards up to 56ºS, near the Beagle Channel, distributing over a 2158 ± 50 km latitudinal range and showing a large-scale distribution pattern across longitudes on the continental shelf. We found a longitudinal segregation be...