It may not be a suitable topic for polite dinner conversation, but it’s a fact that the guanay cormorant has no equal when it comes to the value and purity of its droppings. Not that you’re very likely to see this bird or its waste products now. But for more than half a century, its excretions were on everyone’s lips, sometimes literally so.

In Quechua, the language of the Inca Empire, the word for this miracle excretion was huanu, but the word came to the West slightly garbled as guano, and so it has remained.For centuries, coastal Peruvian farmers had been fertilising their crops with a fine yellowish powder scraped from a few offshore islands. The food plants that grew in their barren soils were bountiful, an agricultural miracle so remarkable that when Alexander von Humboldt and Aimé Bonpland were on the coast at the start of the 19th century, they hurriedly acquired samples of the powder, although they had no idea of its provenance.

Back in Europe, the samples were passed on to the continent’s leading chemists for analysis. They found the mysterious powder to be rich in both nitrogenous compounds and phosphates, but failed to appreciate its potential. So, for the time being, guano remained hidden in the rarified world of analytical chemists, its existence reported on just a few pages in a couple of scholarly publications.

As every green-fingered gardener and farmer knows, plants require a few key nutrients in order to grow and thrive. Among these, nitrogen and phosphorus are absolutely essential, the former for growth and the latter for photosynthesis. Although 78 per cent of the Earth’s atmosphere is made up of nitrogen, plants can’t assimilate it from the air. Instead, as with phosphorus, they take up nitrogen from the soil by assimilating the appropriate compounds.

Sustaining both the nitrogen and phosphorus levels in the soil has always been an uphill struggle for farmers, and they are constantly on the lookout for other sources to plough back into their fields. Before the 1840s, this meant using farmyard and recycled urban waste (mostly ‘night soil’) for nitrogen and crushed bones for phosphorus. But with population growth and urbanisation booming on both sides of the Atlantic, farmers suddenly found themselves staring at falling yields. The nightmare of soil exhaustion, as nutrient replenishment lagged behind uptake, was becoming a reality.

Turning guano into gold

In 1838, while guano languished in the European cabinet of curiosities, in Lima, two enterprising Franco–Spanish merchants, convinced of guano’s magic (“the base manure could well be transformed into the purest gold”) and its market, had samples sent to Liverpool, to a successful merchant named William Myers, who had farming interests. Myers handed it out to his farmer friends to experiment with.

The next harvest gave Myers the answer he was hoping for. English farmers, he told his friends in Lima, would pay a good price for this guano. And to show he meant business, Myers put up the money to get the trade rolling. Early in 1841, a ship laden with just over 2,000 tonnes of guano cleared the port of Callao in Peru bound for Liverpool.

The guano found its way to fields across the UK, where farmers cautiously experimented. One of the first to report their findings was James Johnston, professor of chemistry at Durham University. His 20-page article, ‘On Guano’, published in the 1841 Journal
of the Royal Agricultural Society, reported favourably on the results from five farms where guano was tested against traditional manures. Farmers were encouraged to try it out for themselves in a scientific manner (which Johnston described in full detail) and to decide whether it was for them.

Rather remarkably for the time, the article ended on a worrying tone, a portent of a catastrophic future. As Johnston put it: “It does not appear, as some have been led to believe, that the supply of this substance on the coast of Peru is by any means inexhaustible.”

As Johnston defined it, guano was confined to a few barren outcrops off the Peruvian coast, one of them being the Chincha Islands, located 200 kilometres south of Lima. These islands, three in number and dryly named North, South and Central, were quintessential guano sites. Dry and brown and, from a distance, having the appearance of “snowy crests of a range of mountains”, the Chinchas were home to millions of sea birds, the guanay cormorant usually being the most common.

Over millennia, the sea birds came to the islands to nest and rest and drop their precious droppings unmolested by humans and other predators. The cool surrounding waters, teeming with surface-feeding anchovies, provided the perfect habitat for the birds. And the islands provided the perfect habitat for guano. The upwelling that brought to the surface the nutrient-rich water that was responsible for the abundance of anchovies, together with the prevailing winds, ensured near-desert conditions, thereby preserving in the excreta the precious nitrogenous compounds that would simply leach away if it rained.

Seasons came and went, and the guano kept piling higher and higher; by the time Europeans first climbed the cliffs and beheld the immense extent of God’s outhouse, estimates put the depth of the droppings at greater than 50 metres.

A flourishing industry

British, European and US farmers flocked to the new fertiliser. To ensure it was the real stuff, farmers were advised to sniff
it: if it smelled like manure, it probably was, but to be certain, they should lick it. Each year, hundreds of ships anchored off the Chincha Islands’ rocky precipices waiting for their turn to load as much pulverised excreta as the Peruvian authorities allowed. Little more than a decade into the trade, the islands boasted a town of 3,000 and an export of almost half a million tonnes per annum.

Before long, people started to look for new sources. After all, if these little specks off the Peruvian coast could hold so much fertiliser, then surely there must be similar specks in other oceans. And, if not claimed by someone else (as were the Chinchas by Peru), then whoever got there first, got it all.

In 1856, the US government passed the Guano Islands Act to enable its citizens to grab what they could. And it worked. Appurtenances, as the outcrops were called for jurisdictional purposes, came in thick and fast. The Pacific, thanks to the federal government’s recent granting of statehood to California, was the first ocean to succumb to US acquisitions. By the middle of the Civil War, the USA had laid claim to 60 of its islands and rocks, tentative first steps in the creation of a US empire.

Then it was the turn of the Caribbean, where a further dozen spots, including the notorious Navassa Island (see The Navassa Island revolt), which the USA wrested from Haiti by force of the gunboat, were claimed. The French and British were equally hard at work, especially in the Pacific, and by the end of the 19th century, hardly anything above sea level didn’t belong to someone.
Nothing, it seemed, would stop the frenzy.

During the early 1850s, British farmers, alarmed at Peru’s control of the Chinchas guano, pleaded with their government to take over the Lobos Islands (where guano was reported to be as thick as mud), even though they were clearly Peruvian possessions.
The Spanish, for their part, under the pretence of a scientific visitation, tried to grab the Chinchas themselves during the mid-1860s, only to be thwarted by a superior Peruvian force.

The mere mention of a new guano find sent European ships scurrying to the reported coordinates. In 1843, for example, word got out that Ichaboe, an outcrop off the southwestern coast of Africa, was covered in a ten-metre-thick layer of guano. In December of the following year, no fewer than 460 vessels crowded around it. By August 1845, the island’s bare rocks were revealed (perhaps for the first time in millennia), and the guano trade ceased as suddenly as it had begun: 300,000 tonnes of excreta had been removed.

Solving the labour shortage

Looking for a guano island was one thing, removing the deposits was quite another. No-one in his right mind would choose to work there. So the earliest workers on the Chinchas were slaves, army deserters and convicts, augmented from time to time by others who were clearly not in their right mind.

Once the boom got under way, the shortage of labour became a real problem. The solution came in the shape of Chinese labourers, or coolies, who, having unwittingly signed contracts that bound them to work for a master for a fixed number of years, were bundled onto waiting ships in Macau and Amoy for the cross-Pacific passage. At least a third never made it to their destination; the conditions on board were reminiscent of those during the trans-Atlantic slave trade.

Those who actually reached the Chinchas must have wished they had died on the crossing. Working more than 120 hours a week under an unrelenting sun; breathing in pungent guano dust that made their lips and noses bleed effusively; suffering from untold diseases and chronic gastrointestinal, respiratory and muscular conditions on a diet too meagre to detail; shifting more than four tonnes of excrement per day without the help of mechanical devices; cajoled and terrorised by mad overseers and half-crazed, half-starved dogs: it’s little wonder that many chose suicide, overdosing on opium, jumping off the cliffs or throwing themselves into the chutes that fed the vast holds of the ships. Few of the 30,000 Chinese coolies who were brought to the Chinchas between 1847 and 1874 survived to the end of their contracts.

Guano’s all gone

Real guano, it became clear, was extremely rare. Although claimants to new deposits referred to them as guano, it turned out that they were generally bereft of nitrogenous compounds. In the Pacific, the same weather system that made the Chinchas so arid produced torrential rain that, over time, leached the excreta of its nitrogen. The same happened in the Caribbean and in the Lobos Islands, located further up the Peruvian coast from the Chinchas.

Professor Johnston’s dire prediction was coming true as the Chinchas were devoured. By 1890, the guano was gone: almost 13 million tonnes of it had been scraped, picked, dynamited and removed in just 50 years. The Peruvian guano industry, and the country’s principal export, lay in ruins.

The guano rush is a familiar story of the wanton destruction of natural resources, but the tale doesn’t end there. For even though the guanay cormorant’s scatological record had been removed, its need to eat, nest and rest continued through the long upheaval. And fresh excrement turned out to have even more nitrogenous and phosphoric compounds than the ancient deposits. The Peruvian government realised that the guanay was “the most valuable bird in the world” and, in 1909, it helped to create a semi-autonomous company, the Compañia Administradora del Guano (CAG), to manage the cormorants for sustainable guano yields.

For half a century, the CAG did well: bird populations and guano production increased – at its maximum, more than 300,000 tonnes of guano were collected – despite the periodic setbacks caused by El Niño events, when warm waters entering from the north substantially reduced the anchovy population. Most commentators agree that, left to its own devices, this programme of sustainability would have continued to be successful.

But then the guano industry ran into something it couldn’t handle: the rapid expansion of a new fishmeal industry based on the same anchovy that the cormorant finds so irresistible. Overfishing and a number of particularly grave El Niño events led to a complete collapse of the anchovy fishery and another obliteration of the guano industry. In the past few years, however, it seems that the birds are back in business. What the future holds is anyone’s guess – it all depends on whether the world still has a taste for guano.