There is nothing particularly new about the business of bird poo in Peru.
There has long been money - once big money - in the potent excrement of anchovy-gorged seabirds such as the Guanay Cormorant and the Peruvian Booby and Pelican.
Peru is far and away the world's main producer of this natural and totally organic fertiliser, used to boost the yields and improve the fields of nearly 1m small organic farmers across its mega-diverse territory.
There are 24 guano distribution points in Peru from the arid coast, to the degraded agricultural land in the Andes and jungle areas, where the soil has lost its nutrients through years of coca cultivation for the illegal cocaine trade.
Organic production is expanding in Peru, with its chocolate winning accolades in France and a coffee called Tunki being named Coffee of the Year by the Speciality Coffee Association of America.
Climbing up the stone path which winds its way up Guanape Sur island, just pecking distance from nesting Peruvian Boobies, you arrive at a ridge.
Above that, on a plateau which workers call the 'pampa', stand tens of thousands of honking Guanay cormorants.
These birds earn their name from the high quality and quantity of their excrement. It's particularly rich in nitrogen and is metres deep in places.
"The truth is this is a lovely job", says Juan Mendez who has spent the last 13 years guarding some of Peru's 21 guano islands along its 3,000km coast.
He remains on the island even when the eight-month collection period is over, guarding against poachers who kill the birds by the hundred and sell their meat in cheap coastal markets.
He also looks out for industrial fishing fleets which enter Peruvian waters in search of its rich anchovy stocks.
"Not everyone can live alone on an island like this. You miss your family but fortunately here there's a mobile phone signal," he says.
This is the birds' domain, all 550,000 of them. The noise is an incessant chorus of honks, squawks and drumming wing flaps.
The boobies squabble for crowded cliff space with their razor sharp blue beaks and manic, penetrating gazes.
With nothing but ocean for miles around, real estate is at a premium.
Rooftops make prime nesting spots and everything is speckled with bird poo. The deposits fall like rain and walking anywhere you get a good sprinkling on your head and clothes.
"This is a renewable resource which you won't find anywhere else in the world," says Rodolfo Beltran, director of Agrorural, Peru's rural development agency.
"The seabirds are the guano factories, so we do all we can to make sure their ecosystem is protected and undisturbed."
That means the collection process has changed little in centuries. It is all done by hand as noisy machinery could scare away the birds.
"The human being is the most adaptable machine ever created," says Martin Pizarro, a 44 year old from the northern coastal city of Chiclayo.
He's one of the few labourers who does not come from the glacial Andean highlands of Peru's Ancash region.
Generations of hardy farmers from rural towns like Caraz and Yungay have done this back-breaking seasonal work for decades.
Earning up to two or three times what they can at home, they sow the profits back into their farmland, planting crops with their earnings.
Workers take home a monthly average of 1,200 Peruvian Soles ($428; £278) which is more than double Peru's minimum wage.
Bags of potential
When you see them work you realise why they are the Andes' finest.
Rising at 4.30am for a couple of mugs of hot quinua porridge, before sunrise they've scaled the steep pathways to where the guano is extracted.
Wearing standard-issue plimsolls and navy 'Agrorural' tracksuits, they sprint down a slippery track carrying 50kg sacks of guano on their backs.
Faces etched with exhaustion, they deposit the sack next to a wooden frame and a chute before jogging back up the hill to the area where other workers bag the guano and stitch the sacks.
Each runner, young or old and some little bigger than the sack on their back, carries around 120 bags each in a morning's work.
Perhaps the big difference from past centuries is that now after an intense morning of work the workers are ready to knock off for the day by 11am. They wash and change and line up for a hearty lunch of rice, meat and potatoes.
As much as 100 tons of guano a day is loaded into waiting boats. Agrorural aims to collect more than 23,000 tons this year from two islands. Officials say the industry is expanding by up 40% a year.
The difference now from centuries past is that the Peruvian authorities are trying to sustainably manage the guano industry which implicitly means protecting the marine ecosystem in which the seabirds thrive.
While the over-exploitation of the past may be gone, scientists warn that the seabird population faces a much greater threat from over-fishing of anchovy stocks, particularly for the fishmeal industry.
The bountiful supplies of fish also depend on the Humboldt current which pushes cold water from the Antarctica up to the Equator.
When this strays away from Peru's coastal waters during the seasonal El Nino weather phenomenon, the impact on this marine ecosystem can be devastating.
The seabird population has recovered from 3.2m to 5m in the last four years, but that barely compares with the 60m birds at the peak of the guano boom.
Facing an array of threats, the long-term survival of the guano industry will depend on close control and ecological management.