Threats to a mixed-species colony of Spheniscus penguins in southern Chile

The Pun̈ihuil islands, oil the coast of Chiloé, southern Chile, have the only known mixed colony of Humboldt (Spheniscus humboldti) and Magellanic penguins (S. magellanicus). Since first reported in 1985, the colony has experienced heavy human disturbance, mainly caused by non-regulated tourist activities and the introduction of domestic goats. On the island closest to shore and most frequently visited by tourists, 28% of dirt burrows have collapsed, mainly by accidental trampling and goat activity. In addition, goats browse the vegetation used by penguins to build their nests. On the island located farthest offshore, with no goats and fewer tourists, only 10% of dirt burrows have collapsed. Comparison with previous population estimates suggests that the colony has declined over the last decade. Considering the important biological value as a mixed colony of Spheniscus penguins, we propose that these islands be officially protected.