"The fowl, which was the only domestic animal known in Easter Island, may have come from the Marquesas where it was present but not from Mangareva where it was absent. Because it was the only domestic animal, the fowl received more attention and honour than in any other part of Polynesia. Fowls became the mark of wealth, and festivals were characterized by gifts and distribution of fowls. In order to protect them from thieves, fowl houses of piled stones were erected to house them at night. Stones were piled up against the entrance and the sound of stones being moved served as an alarm to the owner. 

Skulls with incised carvings, imbued with power by Makemake, were placed in the fowl house to promote the egg-laying capacity of the occupants. It may seem a long call from the domestic fowl to the sooty tern, but both are birds and lay eggs. The sooty tern (manu tara) comes to breed in large numbers in July or August off the southwestern point formed by the crater of Rano-kao on three rocky islets, of which the only one accessible to swimmers is Motu-nui. 

What commenced as an ordinary food quest for eggs became an annual competition to obtain the first egg of the season. The warriors (matatoa) of the dominant tribe entered servants for the annual Derby, and members of defeated tribes were not allowed to take part in the competition. The selected servants swam over to Motu-nui and waited in caves for the migration of the birds. 

The warriors and their families assembled on the lip of Rano-kao that overlooked the course. Owing to the strong wind, they built houses of stone for shelter at the village named Orongo, the Place-of-listening. There they listened for the coming of the birds and waited for the call of the successful servant who found the first egg. While waiting they amused themselves with singing and feasting and carved on the adjacent rock figures with birds' heads and human bodies, the symbol of Makemake, god of fowls and sea-birds.

In time, rules and ritual were developed about this annual competition which became the most important social event on the island. The successful servant leaped onto a rocky promontory and shouted across the water to his master 'Shave your head. The egg is yours.'

A sentry on watch in a cave below Orongo, termed the Bird-listener (Hakaronga-manu), heard the call and relayed the message up to the waiting masters. The successful master was termed the Bird-man (Tangata manu). On reception of the egg, the people escorted him to Mataveri, where a feast was held in his honour. After that he went into seclusion for a year in a house at Rano-raraku.

The details of his functions and privileges are not known, but certain it is that he was held in high honour and provided with food by the people until the next annual Derby took place. The list of Bird-men was memorized and transmitted like a list of kings. 

The bird cult is not known elsewhere in Polynesia and is clearly a local development arising out of peculiar local conditions. The importance of the fowl as the sole domesticated animal, the annual migration of the sooty tern to a near-by islet to breed, the village of Orongo with its carved rocks overlooking the course, and the development of the bird cult are all in a natural sequence that could have occured nowhere else but on Easter Island." (Peter H. Buck , Vikings of the Pacific.)

Radically different and less prosaic is Graham Hancock's version (in his Heaven's Mirror. Quest for the Lost Civilization.):

... The dream soul of Hau Maka continued her journey and went ashore on the (actual Easter) Island. The dream soul saw the fish Mahore, who was in a (water) hole to spawn (?), and she named the place 'Pu Mahore A Hau Maka O Hiva' ...

Perhaps Pu Mahore refers to something similar to the star Baten Kaitos, a place where there is a hole through which Sun will be released:

Mahore also means 'to peel off' - like when Odysseus peeled off his beggar's clothes (when he emerged from the 'dark cloth'). Raven had a marten-skin blanket with a hole through which he peered (cfr peeled) before he untied (tara) himself, and in the Indian rope trick a cape or blanket was used to cover the limbs of the cut-up boy:

... the rope would seem to rise high into the skies, disappearing from view. The boy would climb the rope and be lost to view. The magician would call back his boy assistant, and, on getting no response, become furious. The magician then armed himself with a knife or sword and climbed the rope, vanishing too. An argument would be heard, and then limbs would start falling, presumably cut from the assistant by the magician. When all the parts of the body, including the torso, landed on the ground, the magician would climb down the rope. He would collect the limbs and put them in a basket, or collect the limbs in one place and cover them with a cape or blanket. Soon the boy would appear, restored ...

In the bird-nester story, we remember, the hero hid in a meat sack, then suddenly emerged and killed the Trickster, cutting him to pieces, yet the Trickster came back to life:

... He then set off to look for his wife and children; he found them again and gave them food, for his rival had deprived the children of food in the hope that they would quickly die of hunger. The hero then hid in a meat sack, jumped on the Trickster and killed him. The corpse was cut up and the pieces scattered. However, the Trickster came back to life. He went away and stopped to rest by a lake, and meditated on death: should death be final or not? On seeing that a stick, then a buffalo turd, and lastly a piece of pith remained afloat after he had thrown them into the lake, he opted for resurrection. However, when a pebble sank, he reversed his decision. It was better that people should die, he concluded, otherwise the earth would quickly become overpopulated. Since that time, people only live for a certain period and die for ever ...

This is a common theme (viz. cutting up a person into pieces) which we ought to understand. It was used already in the myth about Osiris:

"... Sorrowing, then, the two women placed Osiris's coffer on a boat, and when the goddess Isis was alone with it at sea, she opened the chest and, laying her face on the face of her brother, kissed him and wept. The myth goes on to tell of the blessed boat's arrival in the marshes of the Delta, and of how Set, one night hunting the boar by the light of the full moon, discovered the sarcophagus and tore the body into fourteen pieces, which he scattered abroad; so that, once again, the goddess had a difficult task before her. She was assisted, this time, however, by her little son Horus, who had the head of a hawk, by the son of her sister Nephtys, little Anubis, who had the head of a jackal, and by Nephtys herself, the sister-bride of their wicked brother Set. Anubis, the elder of the two boys, had been conceived one very dark, we are told, when Osiris mistook Nephtys for Isis; so that by some it is argued that the malice of Set must have been inspired not by the public virtue and good name of the noble culture hero, but by this domestic inadventure. The younger, but true son, Horus, on the other hand, had been more fortunately conceived - according to some, when Isis lay upon her dead brother in the boat, or, according to others, as she fluttered about the palace pillar in the form of a bird.

The four bereaved and searching divinities, the two mothers and their two sons, were joined by a fifth, the moon-god Thoth (who appears sometimes in the form of an ibis-headed scribe, at other times in the form of a baboon), and together they found all of Osiris save his genital member, which had been swallowed by a fish. They tightly swathed the broken body in linen bandages, and when they performed over it the rites that thereafter were to be continued in Egypt in the ceremonial burial of kings, Isis fanned the corpse with her wings and Osiris revived, to become the ruler of the dead. He now sits majestically in the underworld, in the Hall of the Two Truths, assisted by forty-two assessors, one from each of the principal districts of Egypt; and there he judges the souls of the dead. These confess before him, and when their hearts have been weighed in a balance against a feather, receive, according to their lives, the reward of virtue and the punishment of sin." (Joseph Campbell, The Masks of God: Primitive Mythology.)

The key member was swallowed by a fish, probably an early variant of the 'whale' (Cetus). The cut up pieces were the pieces of a man (tagata):

etc