An Oasis in the Driest Desert
Along the coast of the Atacama Desert, one of the driest places on Earth, lives an unlikely resident: the Humboldt penguin (Spheniscus humboldti). This medium-sized penguin, which stands 56-70 cm tall, lives on rocky islands and coasts, with a major breeding colony located on Isla Chañaral. This island is part of the Humboldt Penguin National Reserve, a protected area for a global population estimated at roughly 23,800 mature individuals.
The penguins' survival here depends entirely on the cold, nutrient-rich Humboldt Current. This powerful oceanic upwelling brings deep, cold water to the surface, with temperatures as low as 16°C (61°F), which is unusually cool for tropical waters. This process fuels massive phytoplankton blooms, which support a productive marine food web. The primary food source for the penguins is the Peruvian anchoveta (Engraulis ringens), a small fish that congregates in enormous schools. The Humboldt Current ecosystem is one of the most productive in the world, accounting for 18-20% of the total global marine fish catch.
Life in the Burrows
Humboldt penguins are monogamous and historically excavated their nests by burrowing into the deep layers of guano (bird droppings) that covered these islands. These burrows, which can be several meters long, provide protection from the intense desert sun and predators. The historic accumulation of guano was so immense that its large-scale extraction for fertilizer in the 19th century destroyed much of the penguins' nesting habitat, forcing them into less ideal caves and scrapes.
Females typically lay two eggs per clutch, and both parents share the incubation duties for about 40 days. After hatching, the parents take turns foraging, often spending around 22 hours at sea per trip, to bring back regurgitated fish for their chicks. The chicks fledge at about 10 to 12 weeks old. The guano itself contains high levels of nitrogen and phosphorus, and nutrient runoff from the islands helps fertilize the sparse terrestrial ecosystems on the nearby mainland.
A Vulnerable Existence
The greatest natural threat to the Humboldt penguin is the El Niño-Southern Oscillation (ENSO). During a strong El Niño event, the upwelling of the Humboldt Current weakens or stops, and warm surface water moves in. This causes the anchoveta populations to plummet or move to deeper waters, beyond the penguins' typical diving range. The severe food shortages lead to mass starvation, nest abandonment, and widespread breeding failure. The powerful 1982-83 El Niño event caused a 65% decline in the Humboldt penguin population in Peru. Due to these recurring threats, combined with overfishing and habitat destruction, the species is listed as Vulnerable by the International Union for Conservation of Nature (IUCN).