They are called opa osanyin. The iron material and the miniature
forged arrows, swords and bells attached to the staff, proclaim the
power of the god of iron, Ogun. Ogun helps the healer penetrate
the dense forests and obtain healing substances.
The staffs take the form of trees with birds gathering at the top.
The birds symbolize the forests, which are the source of medicine and
healing. They also represent witches, who change into birds to attack
their victims at night. So the presence of birds on the staff relate
to both the healing substances found in the forest and the spirits that
the healers are trying to combat.