We came upon this sighting after the actual attack, and not really sure if the harrier was the perpertrator, if it was, it would be some feat as they aren't a lot bigger than the guinea fowl itself.
It settled down to feed after we approached as stealthly as one can in a vehicle.
D4 500 f/4 VRII 1/1000s f/5.6 ISO400 around 20% crop. Bean bag from front pax seat.