The History of Bird Guano That Changed the Global Economy
Throughout human history, one of the greatest challenges in agricultural production has been maintaining soil fertility. With every harvest, the soil loses nutrients needed by plants, creating a constant need for new sources of nourishment. Today, much of this need is met through chemical fertilizers. However, before synthetic fertilizers were developed, one of the world’s most valuable natural fertilizer sources was seabird droppings known as guano. The guano deposits along the coast of Peru became a strategic resource that influenced the global economy in the 19th century and even caused wars between countries.
Guano is a natural fertilizer formed from the droppings of seabirds accumulated in the same regions over centuries. Because it contains high levels of nitrogen, phosphorus, and potassium, it is extremely effective in agricultural production. Although the importance of nitrogen, now regarded as one of the essential elements of plant nutrition, was not scientifically understood until the 18th century, the indigenous peoples of South America had discovered the agricultural value of guano centuries earlier.
The Use of Guano in the Pre-Inca Period
Archaeological research shows that pre-Inca societies living along the coast of Peru used guano in agriculture from approximately AD 1000 onward. Coastal civilizations such as the Chincha culture collected fertilizer accumulated on islands inhabited by seabirds, transported it to agricultural lands, and significantly increased crop yields.
The Inca Empire later turned this system into a state policy. Inca rulers placed the guano islands under direct state control and established regulations determining which regions could obtain fertilizer from which islands. Great importance was placed on protecting seabirds, and disturbing the birds during breeding seasons or collecting guano without permission was punished severely. These practices are regarded as one of the earliest examples in history of the sustainable management of natural resources.
Europe’s Introduction to Guano
For many years, Europe was unaware of the value of guano. During his travels through South America between 1802 and 1804, the German naturalist Alexander von Humboldt examined the guano deposits along the coast of Peru, collected samples, and brought them to Europe. Thanks to Humboldt’s work, European scientists recognized guano’s extraordinary fertilizing effect.
By the middle of the 19th century, Europe’s rapidly growing population and increasing need for agricultural production greatly increased demand for natural fertilizers. As the Industrial Revolution caused urban populations to expand and made greater food production necessary, guano became one of the world’s most valuable agricultural raw materials.
The Strategic Importance of the Guano Islands
The Chincha Islands off the coast of Peru contained the richest guano deposits in the world. Because the region’s extremely arid climate received almost no rainfall, seabird droppings had accumulated for thousands of years without decomposing. In some areas, guano layers reached thicknesses of dozens of meters.
Three seabird species played the main role in the formation of guano:
- Guanay cormorant (Leucocarbo bougainvillii)
- Peruvian booby (Sula variegata)
- Peruvian pelican (Pelecanus thagus)
Because these birds feed on the abundant fish resources provided by the Humboldt Current, they produce droppings that are extremely rich in nitrogen. At the same time, the arid climate of the Peruvian coast allowed this valuable fertilizer to remain preserved for thousands of years.
The Guano Economy
Between 1840 and 1870, Peru became the world’s largest exporter of guano. Revenue from guano sales became one of the principal sources of income for the national economy. The Peruvian government built railways, improved its ports, and financed numerous public investments with this revenue.
During the same period, European countries and the United States also began showing great interest in guano. Under the Guano Islands Act, enacted by the United States Congress in 1856, American citizens were granted the right to claim unclaimed guano islands on behalf of the United States. As a result, many islands in the Pacific and the Caribbean gained strategic importance because of their guano resources.
Guano and the War of the Pacific
Toward the end of the 19th century, not only guano but also natural sodium nitrate deposits gained significant economic value. In particular, the nitrate reserves around the Atacama Desert were used as agricultural fertilizer and in the production of explosives.
This economic rivalry eventually led to the outbreak of the War of the Pacific in 1879 between Chile, Peru, and Bolivia. One of the main causes of the war was the struggle to control the nitrate and guano deposits in the Atacama region. At the end of the war, which lasted approximately five years, Chile captured important mining regions, and Bolivia lost its access to the sea. This event is regarded as one of the most significant historical examples of how natural resources can influence international politics.
Why Did Guano Lose Its Importance?
At the beginning of the 20th century, the Haber–Bosch process, developed by German chemist Fritz Haber and engineer Carl Bosch, made it possible to produce ammonia on a large scale from atmospheric nitrogen gas. This marked the beginning of synthetic nitrogen fertilizer production and rapidly reduced dependence on natural guano deposits.
This development directly affected not only agriculture but also global population growth. Today, a large proportion of nitrogen fertilizers are produced using the Haber–Bosch process. Nevertheless, guano continues to be used as a valuable natural fertilizer in organic agriculture.
The Status of Guano Today
Although guano has largely lost the economic and strategic importance it held in the 19th century, it has not disappeared as a resource. Peru, in particular, remains one of the world’s most important producers of natural guano. Today, however, guano production is not carried out as a large-scale and uncontrolled mining activity as it was in the past; instead, it is conducted in a limited and planned manner under environmental protection regulations.
The guano islands along the Peruvian coast still provide a habitat for millions of seabirds. These regions are protected by organizations affiliated with the Peruvian government, and guano harvesting is carried out during designated periods. The Chincha Islands, the Ballestas Islands, and other small islands along the Peruvian coast remain among the principal areas where guano production continues today.
However, the bird populations that once formed the foundation of the guano trade now face various threats. Overfishing, climate change, changes in sea temperatures, and the deterioration of ocean ecosystems can affect the number of seabirds that produce guano. The El Niño weather phenomenon, in particular, can reduce fish populations along the Peruvian coast and cause serious declines in seabird colonies.
Today, guano is primarily valued as a natural fertilizer used in organic agriculture. Although it is produced in quantities too limited to compete with chemical fertilizers, it is preferred by farmers who grow high-quality agricultural products because of its natural composition. Its richness in nitrogen and phosphorus makes it particularly suitable for use in vegetable, fruit, and specialty crop production.
The Peruvian government now views guano resources less as a source of economic income and more as a natural heritage that must be protected. The protection of seabirds, preservation of the ecological balance of the islands, and controlled harvesting methods form the foundation of modern guano management.
Today, guano is no longer a strategic resource capable of causing wars between countries as it once was. However, from a historical perspective, it is remarkable that bird droppings could transform global agriculture, international trade, and the political history of South America.
In the customs tariff schedule, the product is classified under heading 3101, and the explanatory notes state: “Guano consists of the accumulated excrement and remains of seabirds and is found in large quantities on certain islands and coasts. It is both nitrogenous and phosphatic and is generally in the form of a yellowish powder with a strong smell of ammonia.” As a matter of trade policy, no tax is imposed; however, the product is subject to veterinary inspections at veterinary border control posts in accordance with the Regulation on Veterinary Controls to Be Conducted on Live Animals Entering the Country and the Regulation on Veterinary Controls for Products Entering the Country.
Conclusion
When we consider the matter, we can see that although the characteristics of this natural product, once a highly important raw material, have not changed with advancing technology, its declining importance stands as an example of how technological developments can affect the commercial development of countries.
Guano is not merely bird fertilizer; it is a strategic natural resource that played an important role in shaping agriculture, economics, and international politics. The history of guano, which began with the Inca civilization’s approach to sustainable resource management, extends to Europe’s agricultural transformation, Peru’s economic rise, and major historical events such as the War of the Pacific. Although it lost its former importance following the development of synthetic fertilizers, guano remains one of the most striking examples in human history of the impact of natural resources on science, agriculture, and the global economy.
References
- Cushman, G. T. (2013). Guano and the Opening of the Pacific World: A Global Ecological History. Cambridge University Press.
- Gootenberg, P. (2005). Between Silver and Guano: Commercial Policy and the State in Postindependence Peru. Princeton University Press.
- Clark, W. C. (1945). The Guano Islands of Peru. Geographical Review, 35(2), 193–214.
- Food and Agriculture Organization of the United Nations (FAO). Reports on soil fertility, organic fertilizers, and sustainable agriculture.
- Servicio Nacional de Áreas Naturales Protegidas por el Estado (SERNANP). Publications on Peru’s marine protected areas and guano birds.
- Instituto del Mar del Perú (IMARPE). Research on Peru’s marine ecosystem, the Humboldt Current, and seabirds.
