Complex sentence: The winner was given a new name and the title "Tangata manu", and great power on the island, including his clan's having sole rights to collect that season's harvest of wild bird eggs and fledglings from Motu Nui.
Split into simpler sentences: The winner was given a new name and the title "Tangata manu", and great power on the island. Including their clan having sole rights to collect that seasons harvest of wild bird eggs and fledglings from Motu Nui.