Satellite tracking of Magellanic Penguin migration

Abstract

We tracked four male Magellanic Penguins (Spheniscus magellanicus) from the beginning of their winter migration for periods ranging from three to six weeks. Upon leaving the colony at Punta Tombo, Argentina where they had bred and molted, all four birds traveled northeast along the coast at speeds consistent with sighting and band-return data which suggest a round-trip winter migration in this species of up to several thousand kilometers. Three of the birds followed a similar route, moved at approximately the same rate, and were still moving northeastward at a distance of over 800 km from the colony when signals ceased. The fourth bird departed from the northeast route at approximately 300 km into its trip and remained in a large bay for at least 29 days, when the last signal was received. Initially, the birds traveled rapidly and made few deep dives. Later, their rate of travel slowed, their paths became more erratic, and they made more deep dives, all indications of probable foraging. This suggests that location of the penguin migration route and rate of travel along it may be determined by seasonal movement of prey. As all birds were within 250 km of shore for the entire period in which signals were received, our results underscore the importance of controlling pollution associated with petroleum transport along the coast of Argentina, currently a major source of Magellanic Penguin mortality.