Kori Bustard (95)
The male Kori Bustard is perhaps the heaviest bird (20-40 pounds) capable of flight (L). In breeding season, the male Kori walks up and down the field with his white tail turned up over his back, and a white neck-sac very inflated under his chin (R). He calls out to the females (ctr) that he knows are hidden in the tall grass. An answer from a female indicates that she will accept him, and he immediately proceeds to join her. [Serengeti, Tanzania].