The Humboldt Penguin population along the western coast of South America is subject to considerable variability, mainly due to El Niño/La Niña. On the Islotas Puñihuil the southern distributional range of Humboldt Penguins overlaps with the northern distributional range of Magellanic Penguins and both species breed sympatrically on a few islands (1,2,3). The foraging ecology during the breeding season (4) and the migration during winter has been studied in both species (5). It could be shown that all penguins, irrespective of sex and species, migrated in a coastal area stretching from the colony about 1000 km northwards.

• (1) Hiriart-Bertrand, L., A. Simeone, R. Reyes-Arriagada, V. Riquelme, K. Pütz & B. Lüthi (2010) Description of a mixed-species colony of Humboldt (Spheniscus humboldti) and Magallanic Penguins (S. magellanicus) at Metalqui Island, Chiloé, southern Chile. Boletín Chileno de Ornitologia 16(1): 42-47
• (2) Reyes-Arriagada, R., L. Hiriart-Bertrand, V. Riquelme, A. Simeone, K. Pütz, B. Lüthi and A. Raya Rey (2013) Population trends of a mixed-species colony of Humboldt and Magellanic Penguins in southern Chile after establishing a Protected Area. Avian Conservation and Ecology 8 (2): 13
• (3) Simeone, A., L. Hiriart-Betrand, R. Reyes-Arriagada, M. Halpern, J. Dubach, R. Wallace, K. Pütz & B. Lüthi (2009) Heterospecific pairing and hybridization between wild Humboldt and Magellanic Penguins in southern Chile. Condor 111(3): 544-550
• (4) Raya Rey, A., K. Pütz, L. Hiriart-Bertrand, R. Reyes-Arriagada, V. Riquelme, B. Lüthi & A. Simeone (2013) Comparative foraging behaviour of sympatric breeding Humboldt and Magellanic penguins reveals sex- and species-specific strategies. EMU 113(2): 145-153
• (5) Pütz, K., A. Raya Rey, L. Hiriart-Bertrand, A. Simeone, R. Reyes-Arriagada & B. Lüthi (2016) Post-moult movements of sympatrically breeding Humboldt and Magellanic Penguins in south-central Chile. Global Ecology and Conservation 7: 49-58 DOI:10.1016/j.gecco.2016.05.001