Guano (seabird droppings) covers the coastal islands and cliffs of Peru in a thick, odiferous, white layer.

Derived from the Quechua word huanu (manure), guano has been used as a natural, nitrate-rich fertilizer since pre-Inca times. The sunny atmosphere of the coast bakes in the nitrates, and lack of rain ensures that the droppings are not washed away.

During the 19th century, Peru’s guano became recognized as the world’s best, and by 1850, it had become the nation’s main export, with nearly one million tons harvested annually.

However, this natural wealth also brought profound political and military consequences.

Such was the economic importance of guano that it was at the heart of two South American wars.

In 1864, a Spanish naval force invaded and occupied the Chincha Islands, which are located just off the Peruvian coast, near Pisco and were the principal source of Peruvian guano, at the time, producing almost 60% of the government's revenue. Knowing their financial importance, the Spanish fleet wanted to use the islands as a bargaining chip in trying to reassert Spanish influence over its former colony. 

The invasion of the Chincha Islands precipitated the Spanish-South American War (also known as the Chincha Islands War), with Peru's neighbours, Chile and Ecuador, siding with her against Spain.

There were a number of inconclusive naval engagements and bombardments of the ports of Valparaiso (Chile) and Callao (Peru). But denied access to any port south of Colombia, the Spanish fleet was unable to re-supply and withdrew in 1866, bringing the hostilities to a conclusion. 

Of far more catastrophic consequences for Peru (and Bolivia) was the War of the Pacific that they fought against Chile from 1879 and 1883.

The background to the war was disputed territory at the frontier between Peru, Chile and Bolivia, in the Atacama Desert. It was given significance by the presence of valuable guano and nitrate deposits in the region. 

None of the belligerents were prepared for war, but Chile's stronger institutions and hard-fought naval dominance eventually led to the invasion of Lima and the surrender of Peruvian forces.

1883's Treaty of Ancon ceded the provinces of Tarapaca, Arica and Tacna to Chile. (Tacna actually returned to Peruvian control in 1929). This treaty also regulated the use of Peru's guano and nitrate resources to repay her debts. 

The War of the Pacific continues to resonate in Peru to this day. Many of the streets and landmarks are named after the 'heroes' of the war, such as Admiral Miguel Grau, Francisco Bolognesi and  Jose Olaya; and there is a national holiday on 8th October every year for Day of the Battle of Angamos, in recognition of the key engagement of the naval campaign. 

By the early 20th century, the supply of guano had been almost completely depleted, so in 1908, the Peruvian government established The Guano Administration to manage the resource.

Today Peruvians continue to harvest guano on about 30 islands and coastal headlands.

Destined primarily for domestic markets, the guano is removed the traditional way - by hand, using buckets and shovels. Labourers live in tents on the islands during harvest season, which occurs approximately every 7 years.

When they leave, these places are once again deserted except for millions of seabirds.

Evidence of the guano industry - along with plenty of marine wildlife - can be seen on a trip to the Ballestas Islands, some four hours south of Lima. Ask us how.