Winter migration of magellanic penguins (Spheniscus magellanicus) from the southernmost distributional range

PÜTZ, K; ADRIAN CARLOS MIGUEL SCHIAVINI; RAYA REY, A; B LÜTHI,

MARINE BIOLOGY

SPRINGER

Lugar: Heidelberg; Año: 2007 vol. 152 p. 1227 - 1235

0025-3162

A total of 22 magellanic penguins (Spheniscusmagellanicus) from Isla Martillo in the Beagle Channel,Argentina, were successfully satellite tracked in 2004 (n = 7),2005 (n = 7) and 2006 (n = 8) to monitor their wintermigration after moult. Only one magellanic penguinmigrated northwards into the PaciWc Ocean, whereas allothers remained in the Atlantic Ocean. In general, thesebirds left the island in an easterly direction, rounded CaboSan Diego, the southeasterly tip of South America, andcontinued northwards occupying inshore waters mostly lessthan 50 km from the coast, only occasionally venturing furtheroVshore. By the end of the transmission period, birdswere still travelling northwards and the most northerlypositions were obtained from birds located in the area ofPeninsula Valdés, Argentina, at a latitude of around 42°S,some 1,500 km from their breeding site on Isla Martillo.The mean maximum distance to the breeding site was,however, only 624 § 460 km. The mean minimum distancecovered during the study period was 1,440 § 685 km,which corresponded to a mean distance of 23.2 § 6.6 kmcovered per day. The northbound migration of the penguinscould be separated into periods of rapid movement, interspersedwith periods during which the birds remained forsome time in particular coastal regions. Areas with a highdensity of daily penguin positions were observed in threedistinct areas: at the northeastern coast of Tierra del Fuego,at the southern entrance of Golfo San Jorge and to thenortheast of the Peninsula Valdez. The observed migrationpattern is presumably driven by the formation and subsequentdispersal of areas of enhanced productivity as theseason progressed. Our Wndings also suggest that magellanicpenguins are increasingly threatened by human activitiesin coastal areas as penguins migrate northwards.