A barren rock island off the coast of Peru. No soil, no water, but hundreds of thousands of birds. For a period of ten years, only two guards may live on Guañape Sur. In the eleventh year though, hundreds of workers arrive for the harvest of the birds' excrement. A long line of men stand on a Peruvian beach. Life vests are handed out. A small boat bobs in the breakers, waiting to take them to a ship further out. A voice from onboard calls out, "Lima is calling! Why this delay?" And then the ship takes the men to Guañape Sur, a guano island 15 miles off the coast of Peru. Once every 11 years, a group of around 200 men spend eight months on this barren cliff - barely deserving of the epithet "island" - collecting the excrement that the hundreds of thousands of seabirds deposit on the land here. Rare meteorological conditions mean that rain does not wash away the excrement. Instead, it hardens to form a layer rich in phosphor and ammonia, which means that it is an excellent fertilizer. But first it must be chipped off, and that is dangerous work: bacteria in the excrement can cause illness or even death. Slow shots show the men as they climb on and off the cliff, shrouded in clouds of powdered excrement, heavy sacks on their backs. A record of a bizarre phenomenon. (IDFA Amsterdam)