I saw both male and female black bellied bustards while at Zimanga Reserve, but only managed to capture a few photos of the male, on a couple of different days. Each time, it was on the ground looking for food, and took off after being startled by the approaching vehicle.
Like most bird species, the female is far drabber in appearance, and lacks the black belly. Unfortunately the only photo I have of a female is completely out of focus as it was shot from the moving vehicle.