Before the tribal wars but after the reign of the King Motu, it was decided on a yearly competition for leadership – the Birdman Journey.
Every year the best warrior was chosen to represent his respective tribal chief. The priests, chiefs and chosen warriors would go to Orongo for the Birdman Competition – no children or women.
The chosen men would swim out to the island off the coast of Orongo – which is one of the calderas on the eastern side of Easter Island. The island is called Motu Nui, it is the biggest island where the Manutara nested.
The men would have to wait for the birds to migrate back to the island to nest in order to take one egg and swim back to Orongo. The first man back would mean his tribal chief would be leader over all the tribes for one year.
This was not a friendly competition either. Men died at the hands of other competitors.
The caldera of Orongo is now used as a natural filter for the potable water on Easter Island. A caldera by the airfield in the west is also used. These calderas collect and filter the water. Easter Island is made of 75 volcanic cones, though not all are obvious.