CONICET | Buscador de Institutos y Recursos Humanos

Magellanic penguins (Spheniscus magellanicus) have been reported to become stranded along the coastsof northern Argentina, Uruguay and southern Brazil during the austral winter. This location is more than a thousand kilometers distant from their northernmost breeding colony in northern Patagonia. Curiously, females typically outnumber males at stranding sites (approximately three females per male). To date, no conspicuous sex differences have been reported in their migratory movements, although records are lacking during the peak stranding season. Consequently, the reason(s) for the female-biased stranding remain unknown, despite the growing necessity for understanding their behavior outside the breeding season. We recorded at-sea distributions of Magellanic penguins throughout the non-breeding period using animal-borne data loggers and found that females reached more northern areas than males and did not dive as deep during winter.