The documentary is about things done after the independent of African colonies, but the culling of the hippopotamuses along the Zambesi River was done in 1963, at which time the surrounding areas were all still controlled by either Britain or Portugal.
There's a scene that shows bodies lined on the ground outside because of lack of space in the morgue, and are surrounded by birds. The subtitles say "The vultures are patiently waiting for their turn, after the operation." The birds are not vultures, but pelicans.