The white stuff on the islands is known as Guano. From the Quechua ’wanu’ is the name given to a substance composed of the excrement of seabirds and used as an effective fertilizer due to its high levels of nitrogen. For that reason guano is an important strategic commodity. Guano has been harvested over several centuries along the coast of Peru, where islands and rocky shores have been sheltered from humans and predators and administered by private and state companies. In this house two guards live all year long protecting the guano.