The Hamerkop is a medium-sized waterbird, standing 56 cm high.
The shape of its head with a long bill and crest at the back is reminiscent of a hammer, which has given this species its name.
The hamerkop is sufficiently distinct to be placed in its own family Scopidae. 
Recent studies have found that its closest relatives are the pelicans and shoebill.
The strangest aspect of Hamerkop behaviour is the huge nest, sometimes more than 1.5 metres across, and strong enough to support a man's weight. 
A mud-plastered entrance 13–18 centimetres wide in the bottom leads through a tunnel up to 60 centimetres long to a nesting chamber big enough for the parents and young. 
Pairs of hamerkop are compulsive nest builders, constructing three to five nests per year whether they are breeding or not. 

Madikwe Game Reserve, South Africa, 19 November 2005