Animal profile

Hoatzin

Opisthocomus hoazin

AvesRiparian and swamp forest, flooded thickets and river marginsLeast Concern

Field profile

The hoatzin is a pheasant-sized bird with a spiky rufous crest, blue facial skin and red eyes, always found close to water. It eats leaves, which is unusual for a bird of its size. It flies poorly and clambers through vegetation. Its evolutionary relationships remain unresolved.

Published field notes

2026-08-07

Hoatzin

The hoatzin ferments leaves in its crop

The hoatzin digests foliage using bacterial fermentation in a greatly enlarged crop, the only bird known to do so. The chamber is so heavy that the bird's flight muscles are reduced to make room for it.

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