"Voyagers down the Pacific coast of South America sail for days through one of the great phenomena of nature and are rarely wiser for the experience. They are impressed by the barren character of the shores and mountain slopes, they marvel at the indescribable abundance of sea-birds without realizing that the existence of both deserts and birds is due to the same cause that induces them to don an overcoast though near the equator." From Frank Chapman's introduction to Robert Cushman Murphy's "Bird Islands of Peru" (1925).
The Humbolt Current (alson known as the Peruvian Current) is an arm of the West Wind Drift that flows up the western coast of South America, bringing cold Antarctic water to the surface along the coast of Chile and Peru. This is one of the largest upwelling zones in the world and supports an immense fish population that in turn attracts great numbers of seabirds and marine mammals. An exciting host of species are endemic to the Humbolt Current: Humbolt Penguin, Markham's Storm-petrel, Hornby's Storm-petrel, Peruvian Diving-Petrel, Peruvian Pelican, Peruvian Booby, Guanay Cormorant, Red-legged Cormorant, Grey Gull, Band-tailed Gull and the stunning Inca Tern. Many others nest elsewhere but use the current as an important feeding ground.
Humbolt Penguin is one of the most threatened penguin species in the world. As of the beginning of 1999, there were only c. 3,300 individuals left in Peru. It is unclear how many perished during the previous El Nino, but current estimates suggest a 45-50% mortality. The main penguin rookery in Peru is on the guano island of Punta San Juan, and is thus extremely vulnerable to commerical guano mining. Dr. Patricia Majluf of the Wildlife Conservation Society based in Lima, Peru has successfully negotiated an agreement with the Peruvian Government to control mining, avoiding the breeding season.
Offshore trips run out of the ocean resort town of Viña del Mar near the city of Valparaiso, not far from Santiago, the capital of Chile. A number of birding tour companies (e.g. Fantastico Sur Birding and Nature Tours) offer pelagic excursions.
Figure 2. Pink-footed Shearwater (with wing raised) and White-chinned Petrel in waters off Chile. Photo copyright of Winty Harrington©, 1999
There are three endemic or near-endemic Pterodroma species breeding on the islands: Stejneger's Petrel, Juan Fernandez Petrel and De Filippi's Petrel. Other important (and near-endemic) breeders are Kermadec Petrel (subspecies juana), Pink-footed Shearwater and White-bellied Storm-petrel (endemic subspecies segethi).
Juan Fernandez Petrel, apparantly a pan-tropical species, breeds on the highest points of Mas Afuera (1650 m), while a few De Filippi's Petrel (also known as Mas a Tierra Petrels) breed at lower altitude on Mas a Tierra closer to the cool waters of the Humbolt Current. An estimated 1 million pairs of Juan Fernandez Petrels breed on Isla Alejandro Selkirk. Pink-footed Shearwaters are common around the islands and breed on Mas a Tierra, but as with the Pterodroma petrels, numbers are fast declining because of predation by non-native cats and coatimundis and through habitat erosion due to feral goats. Magellanic Penguins are also possible.