Guano: The bird’s bounty

Islands like Guañape Norte and its feathered inhabitants have been at the centre of one of Peru’s most lucrative enterprises for hundreds of years. Once the site of a booming trade that changed the face of intensive modern agriculture, Peru is emerging once more as the world’s largest producer of organic fertiliser. The health of Peru’s ocean and the seabirds that call it home underpins the nation’s economic success.
Photo by Tomás Munita

‘Guano’, derived from the Andean Quechua language, is the name given to accumulations of bird droppings used as fertiliser. The dry climate of Peru enables guano to build up in mineral-rich layers on the coastal islands where seabirds roost and breed. Spanish colonial records report guano as a resource prized by the Inca to enrich agricultural soils. Demand for guano fertiliser boomed worldwide in the 1800s, but exports declined after Fritz Haber developed the Haber–Bosch process of nitrogen fixation in 1909 and synthetic fertilisers replaced guano.
Photo by Tomás Munita

The Guañape Islands rise, rocky and dry, from the Pacific Ocean off the coast of northern Peru. The two largest islands to the north and south are Isla Guañape Norte and Isla Guañape Sur and, together with the smaller Islotes Cantores and Islotes Los Leones, they are a haven for Peruvian boobies, Guanay cormorants, Inca terns, Peruvian pelicans and Humboldt penguins. The islands were declared protected areas in 2009 by the National Wildlife Refuge System of Peru.
Photo by Tomás Munita

The Peruvian boobies that wheel in the skies over Guañape Norte choose to breed on coastal islands, nesting on steep slopes and cliff edges or on bare ground. The species is the second most abundant seabird in the region, but its numbers plummeted from an estimated three million birds in the mid-1900s to fewer than 200,000 birds after an El Niño event in the 1980s. The Guanay cormorant, dubbed the ‘billion-dollar bird’, is Peru’s most important guano producer.
Photo by Tomás Munita

Today the growth in demand for organic produce has reinvigorated the Peruvian guano industry after its importance waned at the end of the 19th century. Scientific studies show that seabird guano increases soil nutrients, plant tissue nutrients and plant productivity. The incentive to market guano as the ideal organic fertiliser is therefore high; could the riches of the 1800s be revived? It was the overharvesting of thick guano deposits that endangered the vital nesting habitats of seabirds in the 1800s; today the threats to seabirds are climate change and overfishing.
Photo by Tomás Munita

Nutrient-rich waters off Peru’s coast host nearly 20% of global industrial fish catches. This is a region of upwelling: year-round surface winds pull microscopic plankton up from the ocean’s depths to bloom at the surface and the Humboldt Current brings cold, nutrient-rich water from Antarctica. This means that food is in abundance for fish – the same fish on which seabirds like the Peruvian booby and the Guanay cormorant depend. Overfishing of the Peruvian anchoveta threatens populations of the cormorant, which is now classified as Near Threatened on the IUCN’s Red List. Seabirds have starved in their millions following declines in anchovy stocks related to El Niño, a phenomenon that scientists worry might be exacerbated by climate change.
Photo by Tomás Munita

The steep cliffs and rugged terrain of Peru’s coastal islands may seem inhospitable to human beings, but to seabirds they are an essential haven. These are the same islands over which two wars have been fought to claim possession, so valuable were their guano-coated rocks. Today the Peruvian government realises that the economic sustainability of the guano islands is only viable if the seabirds and the marine ecosystem on which they depend is managed. Walls restrict access to sensitive nesting areas and the region has been declared a marine protected area as part of the Guano Islands and Capes National Reserve System.
Photo by Tomás Munita

The process of guano mining has changed little in hundreds of years, as mechanisation of the labour typically done by hand would potentially frighten away the very birds on which this industry depends. The work is back-breaking: men carry 50-kilogram (110-pound) bags of guano up and down the island’s steep paths to load up to 100 tons of their product into the waiting transport boats. Seasonal workers labour on the island for months at a time, earning about 1,200 Peruvian soles (US$360) per month for their efforts.
Photo by Tomás Munita

Guano that has accumulated over years hardens into solid layers under the harsh Peruvian sun. During the so-called Guano Era in Peru, the economy blossomed thanks to exports to Europe. However, when those exports crashed, bringing the era to an end, Peru was left none the richer for its stint as the world’s largest producer of fertiliser. Today, seasonal workers of mostly Quechua heritage harvest guano under stricter controls. What sustainability in guano mining looks like in the coming years will have consequences for both seabirds and the miners who earn their livelihood in the industry.
Photo by Tomás Munita