The horned coot (Fulica cornuta) can be found in Chile, Argentina and Bolivia, high in the Andes Mountains.
It is sometimes known as Bonaparte's horned coot because it was identified by the French naturalist Charles Lucien Bonaparte in 1853.
Horned coots belong to the family Rallidae.
The horned coot is known for its unusual nest, which consists of a large mound of stones topped with soft vegetation.
Horned coots are large birds, between about 1 ½ and 2 feet long.
They are black, with yellow bills and green legs.
Both male and female horned coots have three fleshy extensions, known as wattles, growing on their foreheads.
The horned coot is in danger of extinction because of habitat loss and because it is hunted by humans and other animals.
The breeding season of the horned coot is between November and January.
Horned coots are monogamous.
They breed in lakes in the mountains, in colonies that can contain up to 80 pairs.
Unlike birds that live in forest habitats, the horned coot does not have access to many leaves or twigs.
Therefore, instead of building a nest out of twigs or leaves, the horned coot makes its nest from stones.
To build a nest, a pair of horned coots carries stones from the shore and piles them up onto a nest site in the water.
They fly back and forth from the shore hundreds of times until they have created a mound of stones that can be up to 13 feet across at its base and 2 feet high, reaching just below or at the water's surface.
Once this mound has been built, the birds search for some bits of vegetation, such as algae, to make the rocky nest more comfortable.
After the eggs are hatched, the male feeds the young by diving into the water to find food.