Hiram Bingham roamed South America in the early 1900s and is credited with rediscovering Machu Picchu in 1911. He relates the following:
The modern Peruvians are very fond of speculating as to the method which the Incas employed to make their stones fit so perfectly. One of the favorite stories is that the Incas knew of a plant whose juices rendered the surface of a block so soft that the marvellous fitting was accomplished by rubbing the stones together for a few moments with this magical plant juice!1
Similar tales were heard by another explorer, Percy Fawcett, who disappeared with his older son in 1925 during an expedition to find an ancient lost city in the uncharted jungles of Brazil:
[A]ll through the Peruvian and Bolivian Montaña is to be found a small bird like a kingfisher, which makes its nest in neat round holes in the rocky escarpments above the river. These holes can plainly be seen, but are not usually accessible, and strangely enough they are found only where the birds are present. I once expressed surprise that they were lucky enough to find nesting-holes conveniently placed for them, and so neatly hollowed out as though with a drill.
‘They make the holes themselves.’ The words were spoken by a man who had spent a quarter of a century in the forests. ‘I’ve seen how they do it, many a time. I’ve watched, I have, and seen the birds come to the cliff with leaves of some sort in their beaks, and cling to the rock like woodpeckers to a tree while they rubbed the leaves in a circular motion over the surface. Then they would fly off, and come back with more leaves, and carry on with the rubbing process. After three or four repetitions they dropped the leaves and started pecking at the place with their sharp beaks, and – here’s the marvellous part – they would soon open out a round hole in the stone. Then off they’d go again, and go through the rubbing process with leaves several times before continuing to peck. It took several days, but finally they had opened out holes deep enough to contain their nests. I’ve climbed up and taken a look at them, and, believe me, a man couldn’t drill a neater hole!’
‘Do you mean to say that the bird’s beak can penetrate solid rock?’
‘A woodpecker’s beak penetrates solid wood, doesn’t it?... No, I don’t think the bird can get through solid rock. I believe, as everyone who has watched them believes, that those birds know of a leaf with juice that can soften up rock till it’s like wet clay.’
I put this down as a tall tale – and then, after I had heard similar accounts from others all over the country, as a popular tradition. Some time later an Englishman, whose reliability I cannot doubt, told me a story that may throw some light on it.
‘My nephew was down in the Chuncho country on the Pyrene River in Peru, and his horse going lame one day he left it at a neighbouring chacra, about five miles away from his own, and walked home. Next day he walked over to get his horse, and took a short cut through a strip of forest he had never before penetrated. He was wearing riding breeches, top boots, and big spurs – not the little English kind, but the great Mexican spurs four inches long, with rowels bigger than a half-crown piece – and these spurs were almost new. When he got to the chacra after a hot and difficult walk through thick bush he was amazed to find that his beautiful spurs were gone – eaten away somehow, till they were no more than black spikes projecting an eighth of an inch. He couldn’t understand it, till the owner of the chacra asked him if by any chance he had walked through a certain plant about a foot high, with dark reddish leaves. My nephew at once remembered that he came through a wide area where the ground was thickly covered with such a plant. ‘That’s it!’ said the chacarero. ‘That’s what’s eaten your spurs away! That’s the stuff the Incas used for shaping stones. The juice will soften rock up till it’s like paste. You must show me where you found the plants.’ When they came to look for the place they couldn’t find it. It’s not easy to retrace your steps in jungle where no trails exist.’2
Percy Fawcett’s younger son, Brian Fawcett, reports the following story, told to him by a friend:
Some years ago, when I was working in the mining camp at Cerro de Pasco (a place 14,000 feet up in the Andes of Central Peru), I went out one Sunday with some other Gringos to visit some old Inca or Pre-Inca graves – to see if we could find anything worth while. We took our grub with us, and, of course, a few bottles of pisco and beer; and a peon – a cholo – to help dig.
Well, we had our lunch when we got to the burial place, and afterwards started to open up some graves that seemed to be untouched. We worked hard, and knocked off every now and again for a drink. I don’t drink myself, but others did, especially one chap who poured too much pisco into himself and was inclined to be noisy. When we knocked off, all we found was an earthenware jar of about a quart capacity, and with liquid inside it.
‘I bet its chicha!’ said the noisy one. ‘Let’s try it and see what sort of stuff the Incas drank!
‘Probably poison us if we do,’ observed another.
‘Tell you what, then – let’s try it out on the peon!’
They dug the seal and stopper out of the jar’s mouth, sniffed at the contents and called the peon over to them.
‘Take a drink of this chicha,’ ordered the drunk. The peon took the jar, hesitated and then with an expression of fear spreading over his face thrust it into the drunk’s hands and backed away.
‘No, no, senor,’ he murmured. ‘Not that. That’s not chicha!’ He turned and made off.
The drunk put the jar down on a flat-topped rock and set off in pursuit. ‘Come on boys – catch him!’ he yelled. They caught the wretched man, dragged him back, and ordered him to drink the contents of the jar. The peon struggled madly, his eyes popping. There was a bit of a scrimmage, and the jar was knocked over and broken, its contents forming a puddle on the top of the rock. Then the peon broke free and took to his heels.
Everyone laughed. It was a huge joke. But the exercise had made them thirsty and they went over to the sack where the beer-bottles lay.
About ten minutes later I bent over the rock and casually examined the pool of spilled liquid. It was no longer liquid; the whole patch where it had been, and the rock under it, were as soft as wet cement! It was as though the stone had melted, like wax under the influence of heat.3
In an interview in 1983, Jorge A. Lira, a Catholic priest who was an expert in Andean folklore, said that he had rediscovered the ancient method of softening stone. According to a pre-Columbian legend the gods had given the Indians two gifts to enable them to build colossal architectural works such as Sacsayhuaman and Machu Picchu. The gifts were two plants with amazing properties. One of them was the coca plant, whose leaves enabled the workers to sustain the tremendous effort required. The other was a plant which, when mixed with other ingredients, turned hard stone into a malleable paste. Padre Lira said he had spent 14 years studying the legend and finally succeeded in identifying the plant in question, which he called ‘jotcha’. He carried out several experiments and, although he managed to soften solid rock, he could not reharden it, and therefore considered his experiments a failure.4
Aukanaw, an Argentine anthropologist of Mapuche origin, who died in 1994, related a tradition about a species of woodpecker known locally by such names as pitiwe, pite, and pitio; its scientific name is probably Colaptes pitius (Chilean flicker), which is found in Chile and Argentina, or Colaptes rupicola (Andean flicker), which is found in southern Ecuador, Peru, western Bolivia, and northern Argentina and Chile. If someone blocks the entrance to its nest with a piece of rock or iron it will fetch a rare plant, known as pito or pitu, and rub it against the obstacle, causing it to become weaker or dissolve. In Peru, above 4500 m, there is said to be a plant called kechuca which turns stone to jelly, and which the jakkacllopito bird uses to make its nest. A plant with similar properties that grows at even higher altitudes is known, among other things, as punco-punco; this may be Ephedra andina, which the Mapuche consider a medicinal plant.5
source ... http://davidpratt.info/andes2.htm