Hamerkop's nest

The strangest aspect of Hamerkop behavior is the huge nest, sometimes more than 1.5 m across, comprising perhaps 10,000 sticks and strong enough to support a man's weight. The birds decorate the outside with any bright-coloured objects they can find. When possible, they build the nest in the fork of a tree, often over water, but if necessary they build on a bank, a cliff, a human-built wall or dam, or on the ground. A pair starts by making a platform of sticks held together with mud, then builds walls and a domed roof. A mud-plastered entrance 13 to 18 cm wide in the bottom leads through a tunnel up to 60 cm long to a nesting chamber big enough for the parents and young.
These birds are compulsive nest builders, constructing 3 to 5 nests per year whether they are breeding or not.