but the guano on everyone’s minds was the nitrogen-rich droppings of cormorants, boobies, and pelicans on the Chincha Islands off the coast of Peru. Islands make attractive rookeries for seabirds in general. The Chinchas had the additional virtue that they hardly ever saw rain. The guano piled hundreds of feet high and baked in the sun, so that the very rock of the islands was centuries’ worth of calcified bird droppings.
