There are a bunch of rocky islands off the port of Callao. We saw the islands from a boat tour organized by the ship. Some of the islands are only home to sea lions or birds. Where there are birds, there is guano. The dry climate preserves the droppings of seabirds like the cormorant.
Teams of laborers from the highlands scrape the dung off the hard soil in the same place where thousands of convicts, army deserters and Chinese indentured servants died. Peru’s government has restricted guano collection to about two islands a year, enabling the droppings to accumulate. Workers smooth slopes and build walls that retain the guano. The walls are shown in the first picture. Because the guano is so valuable as a source of income for the government, there are armed guards at each of the islands to ward off threats to birds, which produce 12,000 to 15,000 tons of guano a year.
According to an article in the New York Times:
In scenes reminiscent of open-pit gold mines on the mainland, the laborers rise before dawn to scrape the hardened guano with shovels and small pickaxes.
Many go barefoot, their feet and lower legs coated with guano by the time their shifts end in the early afternoon. Some wear handkerchiefs over their mouths and nostrils to avoid breathing in guano dust, which, fortunately, is almost odorless aside from a faint smell of ammonia.
Fondest memory: Most of the tips will be under Isla San Lorenzo, which is the biggest island off the port and has a famous lighthouse on it.