Phoeniculus purpureus
With mixed green and violet woodhoopoe bird parties in Namibia, I had to wait for the light to shine on the back of this bird (and reveal its purple gloss) before I could confirm the sighting.
Fortunately I was able to see this species on a number of occasions while travelling through Namibia in July 2012; first in Kunene with Pete Morgan and then outside our chalets in Halali camp, Etosha.