|Hoatzin (Opisthocomus hoazin)
A prehistoric looking bird with a punk haircut, there is considerable debate about which birds are most closely related to the Hoatzin. Traditionally it has been placed in the Galliformes along with pheasants, turkeys, curassows, etc.. More recently it has been placed with the cuckoos and some gene sequencing carried out by JM Hughes and AJ Baker at the Royal Ontario Museum suggests that its closest relatives are the turacos of sub-Saharan Africa.
|Whatever its parentage, it is a pretty unique beast. It only eats leaves and is the only bird to have a gut like a cow where the cellulose from the leaves is broken down into sugars. This in turn requires a specially adapted skeleton and the weight of leaves it eats makes it fairly ungainly as it flies or clambers about the dense vegetation of its habitat.|
|Adding to the interest is the fact that the nestlings have claws on their wings. When threatened, they fall out of the nest, which is usually over water, and when the danger is passed they use their wing-hooks to help them climb back into the nest. |
The Hoatzin is found in both the Amazon and the Orinoco basins of South America and is usually in fairly large groups.
There is an excellent article in HBW, Volume 3, Pages 24 to 32.