African darter.
The alternate name of "Snakebird" comes from the swimming method employed by Darters. They swim very low in the water, often with just their head and neck protruding above the surface. They spear their prey (mainly fish but also other aquatic animals eg snakes, frogs, crustaceans etc) underwater as they swim along. They nest communally alongside cormorants, ibises, herons and egrets.