The taiaha is not meant for throwing but for hand to hand fighting and thrusting under the neck. Just behind the head of the taiaha would be a tuft of white feathers to help distract the enemy. The eyes are of paua shell. Notice the similarity of patterns even though from different iwi (tribes) http://www.youtube.com/watch?v=MVQNHFCGl1w
The whale bone patu is used similarly, not for bopping on the head. Patu also means to hit or strike.