About Opisthocomus hoazin (Statius Muller, 1776)
Size
The hoatzin, Opisthocomus hoazin, is pheasant-sized, with a total length of 65 cm (26 in).
Head and Neck Features
It has a long neck, a small head, an unfeathered blue face, and maroon eyes, with a spiky rufous crest on top of its head.
Tail Appearance
Its long sooty-brown tail is bronze-green, ending in a broad whitish or buff band.
Upper Body Coloration
The bird’s upper body is dark: wing coverts have dark sooty-brown edges with buff coloring, while the mantle and nape are streaked with buff.
Underpart Coloration
Its underparts are buff.
Rufous Plumage Details
The crissum (the undertail coverts surrounding the cloaca), primary flight feathers, underwing coverts, and flanks are a rich rufous-chestnut, though this coloring is mostly only visible when the hoatzin opens its wings.
Vocalizations
This is a noisy bird that produces a range of different hoarse calls, including groans, croaks, hisses, and grunts.
Associated Body Movements
These calls are often paired with body movements, such as spreading the wings.
