MEPS 335:217-225 (2007)  -  doi:10.3354/meps335217

Oceans apart: conservation models for two temperate penguin species shaped by the marine environment

P. Dee Boersma1,*, Ginger A. Rebstock1, David L. Stokes2, P. Majluf3

1Department of Biology, Box 351800, University of Washington, Seattle, Washington 98195-1800, USA
2Department of Interdisciplinary Arts and Sciences, Box 358530, University of Washington Bothell, Bothell, Washington 98011, USA
3Unidad de Biologia de la Conservacion, Universidad Cayetano Heredia, Armedariz 445, Lima 18, Peru

ABSTRACT: Oceanographic productivity patterns in the breeding areas of Magellanic penguins Spheniscus magellanicus in the Atlantic differ from those of Humboldt penguins S. humboldti in the Pacific. We used satellite telemetry to compare foraging trips between 2 Humboldt penguin females with chicks and 44 Magellanic penguin females with eggs or chicks. The Humboldt penguins took trips of short duration and distance, with fewer than 10% of locations >25 km from the colony. Magellanic penguins traveled longer and more variable distances. Only 24% of locations during chick rearing were within 25 km of the colony; all 8 incubation trips reached distances greater than 100 km. Among Magellanic penguins, foraging trip duration was significantly correlated with distance from the colony during all stages of the breeding season (incubation r2 = 0.66; early chick r2 = 0.75; late chick r2 = 0.91). For each hour of trip duration, penguins ranged nearly 1 km farther from the colony. For the 2 Humboldt females, trip duration was correlated with maximum distance from the colony for one female but not the other, whose trip duration varied little. Trip duration for Magellanic penguins determined by nest checks was correlated with duration determined by satellite telemetry (r2 = 0.96), making nest checks a potentially inexpensive and minimally disturbing estimator of foraging trip distance and changing food availability. The large difference in foraging distance between the species reflects the distribution of productivity in their foraging areas and shows that protecting the species requires conservation models that are effective on different spatial scales.

KEY WORDS: Spheniscus magellanicus · Magellanic penguin · Spheniscus humboldti · Humboldt penguin · Foraging range · Conservation model · Marine protected area · Management zone

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