Wes, Chokwe, called cimbuya.
Used for divination ceremony, it is standing on a heap of sand and the wizard is dancing around, when the axe fall down, he take a look to it and the signs in the sand are interpreted.
The blade and the head axe represent a bird : engoulevent (in french)
http://en.wikipedia.org/wiki/European_Nightjar
Perhaps your model is broken at the top ?
Luc