Authority derives from the age-group and the age-set. Prior to circumcision a natural leader or Olaiguenani is selected; he leads his age-group through a series of rituals until old age, sharing responsibility with a select few, of whom the ritual expert (Oloiboni) is the ultimate authority. Masai youths are not circumcised until they are mature, and a new age-set is initiated together at regular intervals of twelve to fifteen years. The young warriors (Il-Murran) remain initiates for some time, using blunt arrows to hunt small birds which are stuffed and tied to a frame to form a head-dress. Traditionally, among the Luhya, boys of certain age-sets, typically between 8 and 18 years of age would, under the leadership of specific men engage in various rites leading up to the day of circumcision. After circumcision, they would live apart from the rest of society for a certain number of days. Not even their mothers nor sisters would be allowed to see them.