Occasionally the characteristic bird figure appears on an artifact that can not be dismissed as natural without some strenuous mental acrobatics.  This is one of them.  The bird is a separate object, somehow cemented onto the pedestal. 

Above:  Typical bird figure.  Below:  The same object flipped vertically, revealing the characteristic two-faced image of a quasi-anthropomorphic face at one end and a bird figure at the other. 

These figures nicely show the particular attention typically given to the carving of the eye.

This figure clearly shows the common motif of a nose in the form of a small bird-like face.

Three photos above:  Typical bird forms.