Humboldt penguin
Humboldt penguins are extremely sensitive to human presence, with little habituation potential. Passing at a 150m distance from an incubating Humboldt penguin provokes a response, which is the greatest response distance reported for penguins to date, making it the most timid penguin species so far studied. Humboldt penguins need up to half an hour to recover to normal heart rates after human approach, however, this time decreases with repeated visitation. Cumulative stress by frequent visits and delayed return of foraging partners leads to nest desertion, consequently causing decreased breeding success at frequently visited sites.