Hoatzins (Opisthocomus hoazin) live in the Amazon rain forest, in the basins of the Amazon and Orinoco Rivers. They perch in colourful groups on tree branches in swamps or along the banks of slow moving rivers. Clumsy on their short legs, and poor fliers, they are nevertheless beautiful birds that tolerate the presence of humans quite well.
An adult Hoatzin is 60cm long (24in), about the size of a Common Raven. The Hoatzin has a small head with a bright blue face and red eyes, and the top of its head is adorned with a crest of tall reddish feathers, all of which makes it look like something out of Dr. Seuss.
Aside from its unique appearance, the Hoatzin has long been of great interest to ornithologists because it is unlike any other bird in several ways. Here are some interesting facts about Hoatzins:
- There is only one genus and species of Hoatzin: Opisthocomus hoazin.
- The relationship of the Hoatzin to other birds is the source of much debate and disagreement. It has been grouped with turkeys and pheasants, cuckoos or turacos, and most recently with doves. Even the results of genetic studies are inconclusive.
- Hoatzins eat mostly young green leaves from rain forest plants. An enlarged foregut containing bacteria helps them break down cellulose and digest their food, an arrangement similar to that found in cattle. Digestion takes many hours, and Hoatzins are often observed resting the sternum on a branch.
- The foregut of the Hoatzin accounts for a quarter of the bird’s weight, and is so large that there is little room for flight muscles. This accounts for the Hoatzin’s poor flying capability.
- Bacterial fermentation smells bad, and so do Hoatzins, earning them the common name of Stinkbird and largely protecting them from being hunted for food.
- Social groups of Hoatzins consist of a pair and their adult (mostly male) offspring. All members participate in the feeding of chicks.
- Hoatzin chicks have two claws on each wing, a feature that makes it easy for them to climb and cling in the branches of trees.
- Hoatzin chicks leave the nest frequently and may even dive into water below the nest when danger threatens. Afterwards, they return to the tree by swimming and climbing back up into the branches.
Other birds of South America and the Falkland Islands:
Sources:
Firefly Encyclopedia of Birds. Perrins, Christopher ed. Buffalo: Firefly Books, 2003
Hoatzin: Opisthocomus hoazin. Arthur Grosset.
More Taxa, More Characters: The Hoatzin Problem is Still Unresolved. Sorenson, Michael D., Elen Oneal, Jaime Garcia-Moreno and David P. Mindell. Mol. Biol. Evol. 20(9):1484-1498. 2003
Mystery Birds: Hoatzin Adults and Young. Cornell Laboratory of Ornithology.
Rosemary Drisdelle - Rosemary Drisdelle has been published many times as a nonfiction writer and several times as a poet. Her first book, Parasites: Tales of ...
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