Hoatzin | Opisthocomidae

Hoatzin | Hoatzin | Hoacín

A family with a single species, the Hoatzin, which in this guide occurs in the Amazonian lowlands of Colombia, Ecuador, Peru and Bolivia, along slow-flowing rivers, oxbow lakes and swamps with dense waterside vegetation. It is a pheasant-sized bird with a long tail, a small head, a ragged crest of stiff feathers, bare blue facial skin and red eyes; the plumage is brown with pale streaks, with rufous primaries. The Hoatzin is the only bird that digests its food in the manner of a ruminant: it eats almost nothing but leaves, which are fermented by bacteria in a greatly enlarged crop. As a result it smells of manure, and the heavy crop makes it a clumsy flier that mostly covers short distances between branches. Groups spend much time sitting still to digest and give hoarse hisses and groans when disturbed. The nest is a platform of twigs over water, and older offspring often help with care. The chicks have two small claws on each wing; when threatened they drop into the water, swim to the bank and climb back up using wings and feet. Its relationship to other birds remains uncertain.