- Opisthocomus hoazin
Identification
62-70 cm; (24 - 26 in); weight 700-900 g; a chicken-sized bird with a "prehistoric" appearance.
Large wings, small head, long neck, long tail. Head almost bare, with frizzy red crest, large bright blue area around eyes, which are red. Short bill. Bronze olive colour above, buff streaks on hindneck and mantle; tail black broadly tipped buff, shoulders pale buff; throat and breast buffy white; remaining underparts and primaries, chestnut coloured.
Sexes similar but female slightly smaller and has lower crest.
Distribution
Occurs only in South America: found in the Guianas and Venezuela south to Bolivia, Peru and Amazonian Brazil. Amazon and Orinoco basin lowlands.
Taxonomy
Appears unrelated to other birds. Has been included in the order Gruiformes and in Cuculiformes but is currently placed in its own order, the Opisthocomiformes.
Subspecies
This is a monotypic species[1].
Habitat
Swamps, mangroves, lowland flood forest, river banks and oxbow lakes. Occurring from lowlands, to 500 m altitude.
They perch on low or middle branches of vegetation overhanging water; occasionally found in treetops, especially when roosting.
Behaviour
They live in pairs in groups of 50 or more.
Action
Weak fliers because of size of crop, which displace some of breast flight muscles; thus they are sedentary and somewhat ungainly.
They perch on branches, while resting on a callous on sternum on branch. When alarmed, open large wings, displaying bright chestnut flight feathers around a large black spot surrounded by white - this simulates an "eye".
Diurnal and nocturnal, tends to rest during hottest part of day.
Diet
Feeds primarily on leaves and shoots of some marsh and swamp plants, mainly arums (philodendron family). Leaves are ground in the large double crop, and ferment there, giving bird a musky odour.
The are not palatable to humans but preyed on by monkeys.
Breeding
Breeds during rainy season. During breeding, they live in small groups of two to ten; a few of which are breeders and the others, "helpers". Entire group incubates eggs and cares for young, which are fed from crop of adult caretakers. Mating probably polygamous and promiscuous.
The nest is a loose stick platform two to eight metres above water. Each nest contains two (occasionally three) creamy oblong eggs spotted with pink, blue or brown. Incubation about 28 days. Newly-hatched Hoatzins almost featherless, but rapidly grow down, and have claws on first and second digits, so they can climb on vegetation. When in danger, they drop into the water, using claws, bills and feet to climb out (they may not return to nest). Claws disappear at time of definitive plumage formation. Remain in nest for several weeks after hatching.
Vocalisation
Defensive call: a wheezing hiss.
References
- Clements, J. F., T. S. Schulenberg, M. J. Iliff, S. M. Billerman, T. A. Fredericks, J. A. Gerbracht, D. Lepage, B. L. Sullivan, and C. L. Wood. 2021. The eBird/Clements checklist of Birds of the World: v2021. Downloaded from https://www.birds.cornell.edu/clementschecklist/download/
- Thomas, B.T., Kirwan, G.M. & Sharpe, C.J. (2019). Hoatzin (Opisthocomus hoazin). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from https://www.hbw.com/node/53530 on 21 July 2019)
- Billerman, S. (2012). Hoatzin (Opisthocomus hoazin), version 1.0. In Neotropical Birds Online (T. S. Schulenberg, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/nb.hoatzi1.01
Recommended Citation
- BirdForum Opus contributors. (2025) Hoatzin. In: BirdForum, the forum for wild birds and birding. Retrieved 25 April 2025 from https://www.birdforum.net/opus/Hoatzin
External Links
GSearch checked for 2020 platform.1
