Hoatzin (Opisthocomus hoazin)

[order] OPISTHOCOMIFORMES | [family] Opisthocomidae | [latin] Opisthocomus hoazin | [UK] Hoatzin | [FR] Hoatzin | [DE] Hoatzin | [ES] Hoatzin | [NL] Hoatzin

Subspecies

Genus

Physical charateristics

Adult Hoatzins are approximately 60 to 68 cm in length. They have blue skin covering their faces and their eyes are red. The outer feathers are primarily chestnut-brown and the long tail is bronze-green and ends in a white band. The heads of Hoatzins are topped with a crest of reddish-brown feathers. The young are born without feathers but develop a layer of black down shortly after birth. A distinguishing feature of young Hoatzins are the pair of functional wing claws which are found on the ends of their wings on the first and second fingers. This feature is lost when the bird matures into an adult.

Listen to the sound of Hoatzin

[audio:http://www.aviflevoland.nl/sounddb/H/Hoatzin.mp3]

Copyright remark: Most sounds derived from xeno-canto

Range

South America : Amazonia

Habitat

The habitat of Hoatzins includes swamps, fresh water marshes, gallery forests, and the banks of rivers, lakes and streams.

Reproduction

Hoatzins do not begin breeding until after their first year of life. The breeding season of Hoatzin occurs during the same time as the rainy season of their territory. Hoatzins build their nests on branches over the water about 2 to 6 meter above the surface. They normally lay two to three eggs and the incubation period lasts 32 days. Both male and female brood the young, which typically remain in the nest for 2 to 3 weeks after they hatch.

Feeding habits

Although they typically feed on less than twelve species of plants, they are capable of eating the leafs of more than fifty different species. The leafs of tropical legume plants are an example of a leaf that Hoatzins commonly feed on. Other foods that are sometimes included in the diet of Hoatzins include some flowers and fruits. Opisthocomus hoazin have developed a special system that allows them to feed on leafs. They have an enlarged crop in which symbiotic bacteria are stored and used to break down the cell walls of the leafs, allowing for them to be digested. This process is called foregut fermentation and O. hoazin are the only birds with this type of digestive system. The bacteria within the crop also act as a source of nutrients for Hoatzins by occasionally getting moved into their stomachs. The bacteria are introduced to young Hoatzins when an adult regurgitates a sticky substance containing large amounts of the bacteria and feeds it to the young.

Conservation

This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be stable, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size has not been quantified, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
Hoatzins are found throughout the Amazon in northern and central South America . In Suriname confined to the banks of the Corantijn River.

Migration

Resident throughout range.

Distribution map