Linda Crampton is a writer and teacher with an honors degree in biology. She loves to study nature and write about living things.

The Stinkbird or Reptile Bird

The hoatzin is a South American bird with some strange features. It’s also called the reptile bird, the skunk bird, and the stinkbird. It's known for its unusual digestion method, an unpleasant smell, clumsy movement, and noisy behaviour. It's also famous for the claws on the wings of the young birds. Thankfully, it isn’t endangered, so we have time to investigate this bizarre bird and its life. In this article, I list forty facts about the hoatzin that may be new to you.

Classification and Origin of a Unique Animal

1. The scientific name of the hoatzin is Opisthocomus hoazin. The species name is spelled differently from the common name of the bird.

2. The bird belongs to the family Opisthocomidae and the order Opisthocomiformes. It's the only member of its genus, family, and order.

3. The exact relationship of the hoatzin to other birds is uncertain. It seems to have had a very ancient origin.

4. Some evidence suggests that the bird originated in Europe. Fossils resembling bones of the hoatzin have been found on the continent. Younger fossils resembling the bird's bones have been found in Africa.

5. Researchers suggest that the birds travelled between continents on rafts of vegetation, as some mammals and reptiles are believed to have done. The continents were once joined together, but they separated long before the deposition of the hoatzin-like bones.

Physical Features of the Hoatzin

6. The hoatzin is about the size of a pheasant and may reach a length of twenty-six inches. Males and females look the same. The bird is quite colourful, especially when its wings are open.

7. The small head bears an untidy crest of long, spiky, and orange feathers. The crest causes some people to refer to the hoatzin as the "punk rock bird". The bird's neck is quite long.

8. The sides of the face are pale blue to sky blue in colour and have no feathers. The eyes are dark red.

9. The undersurface of the neck and body is buff or orange.

10. The wings are dark brown, grey, or black, except for the outer feathers, which are a lovely red to rusty-red colour. The sides of the body under the wings are orange or a shade that is referred to as "rufous-chestnut".

11. The tips of the dark tail feathers are buff to yellow in colour.

Distribution and Habitat

12. The hoatzin is found in the northern part of South America in many countries. The countries are shown on the map below and include:

• Bolivia
• Brazil
• Colombia
• Ecuador
• French Guiana
• Guyana
• Peru
• Suriname
• Venezuela

13. The bird is often seen perched on trees and shrubs in wetlands. It's found in areas with dense vegetation that are beside slow-moving rivers, lakes, and swamps.

14. The hoatzin is the national bird of Guyana.

Diet, Digestion, and Odour

15. Hoatzins are herbivores. They are said to be folivorous because they primarily eat leaves, though they eat some buds, flowers, and fruits as well.

16. The birds may accidentally ingest insects that are on the plants that they eat, but they don't deliberately seek these animals out.

17. The digestive tract of a bird contains extra chambers compared to that of a human, as shown in the illustration above. The crop is a pouch joined to the esophagus. The stomach consists of two sections: the proventriculus and the gizzard.

18. The hoatzin's lower esophagus and crop are unusually large. Bacterial fermentation of food in this area helps to break down food so that it can be absorbed. The process is similar to that in the rumen of a cow. The crop contains ridges that help to break the food up. The hoatzin is the only bird known to carry out foregut digestion.

19. The fermentation produces chemicals that can smell unpleasantly like dung to humans. They are released from the bird's gut, giving the animal the name of skunk bird or stinkbird.

20. There is some debate about how common or strong the bird's smell is. It may be variable in appearance or strength or it may be strongest for people who are particularly sensitive to the odour.

21. The birds appear to get most or all of the water that they need from the leaves that they eat because they are rarely seen drinking.

Hoatzins in effect are flying cows: their diet primarily is young leaves and buds, which are digested in the crop with the aid of bacteria and microbes.

— Cornell Lab of Ornithology

Lifestyle

22. Hoatzins are very social animals and are sometimes seen in small or large groups.

23. They appear to feed early and late in the day. At other times, they preen their feathers, sunbathe with open wings, or wash in puddles of rain trapped in the trees.

24. The birds are frequently detected by the sounds that they make. They are often very audible as they crash through the trees and vocalize.

25. Hoatzins produce several kinds of sounds, including grunts and croaks. The sounds enable the birds to remain in contact with each other. The birds also hiss when protecting their chicks.

26. The bird's sternum (breastbone) is reduced in size, apparently due to the space occupied by the enlarged crop. Flight muscles are attached to a bird's sternum. The small sternum of the hoatzin contributes to its weak ability to fly.

27. The birds spend most of their time climbing over branches instead of flying through the air. When they do fly, they travel only short distances.

28. Hoatzins exhibit a behaviour known as sternal perching. They rest their sternum on a branch as they perch.

Reproduction

29. Reproduction occurs during the rainy season.

30. Hoatzins aren't territorial during most of the year but become so during the breeding season. The breeding pair and several helpers defend the area around the nest.

31. In some cases, it's known that the helpers are offspring from the previous clutch. Hoatzins don't breed during their first year of life.

32. The birds nest in colonies. They defend the nest area from members of their own species and from predators.

33. The female creates a nest made of sticks in tree branches that overhang flooded land. A clutch consists of one to three eggs.

34. The eggs are incubated for around thirty-two days.

35. Researchers have discovered that the helpers aid in building the nest, incubating the eggs, and rearing the chicks.

Hoatzin Chicks

36. The chicks have two claws on the front of each wing. These are eventually lost. They remind some people of the three claws on each wing of Archaeopteryx, a prehistoric animal with both dinosaur and bird-like features. There is no evidence that hoatzins are related to Archaeopteryx, though.

37. If an avian predator such as a hawk approaches the nest, the adults try to distract it. The claws help the chicks to climb over branches and hide from the predators.

38. The youngsters have another way to protect themselves. They drop from the nest into the water of the flooded land below. They can actually swim underwater and then find their nesting tree.

39. The young birds climb up the tree trunk with the aid of their claws until they reach the nest. Their escape mechanism can be helpful, though sometimes the water contains predators eager to eat the chicks.

40. For up to two months after hatching, the chicks feed on food regurgitated by an adult. When they swallow the regurgitated material, the chicks obtain the bacteria that they need for digesting plants.

Population Status

The IUCN (International Union for Conservation of Nature) classifies the hoatzin in its "Least Concern" category. This classification is based on a 2016 population assessment. The bird is sometimes hunted for food, although it's said that its smell discourages this activity. In addition, its habitat is sometimes destroyed. In general, though, it appears to be doing okay at the moment. The IUCN does say that its population is decreasing, however, which could be a warning for the future.

Hoatzins are unusual birds and an interesting part of nature. The birds are hard to keep alive in captivity and haven't survived for long in this situation. There may be important facts about their biology still to be discovered. Hopefully, we will soon learn more about their life and their origin.

References

• The hoatzin: a misfit and a genetic mystery from the Audubon website
• Information about the bird from the Encyclopedia Britannica
• The hoatzin may have originated in Europe from the phys.org new service
• An earlier article suggesting an African origin of the bird from phys.org
• Opisthocomus hoazin facts from the Red List of the IUCN (International Union for Conservation of Nature)

Questions & Answers

Question: Do Hoatzins poo (or defecate)?

Answer: Hoatzins and other birds do produce feces, but it’s released with their urine instead of on its own. The waste substances exit the body through an opening called the cloaca.

Question: What if you brought the stinkbird to the desert to live permanently?

Answer: The bird would be unable to survive unless it was kept in an enclosure with a suitable environment. Hoatzins live in vegetation beside wetlands. Their natural environment is very different from that of a desert. They are also social animals that associate with other members of their species. Even if a special enclosure contained environmental conditions that kept a hoatzin alive, it would be highly unlikely that the bird would be content in it.

© 2018 Linda Crampton

Comments

Linda Crampton (author) from British Columbia, Canada on August 13, 2018:

Hi, Suhail. Thanks for the visit. The crow pheasant is currently classified in the cuckoo order and family, although it's non-parasitic. The hoatzin is classified in a different order and family, so biologists don't think that the birds are closely related.

Suhail Zubaid aka Clark Kent from Mississauga, ON on August 13, 2018:

Never heard of this bird before. I am so glad that I learn everyday about an animal that I had never heard of before. I am surprised that such a wide ranging bird is not covered in wild bird books as all.

The older bird looks much like crow pheasant or coucal pheasant of Asian Subcontinent. Are we sure that they are not related?

Regards,

Suhail

Linda Crampton (author) from British Columbia, Canada on August 05, 2018:

Thank you, Ann. I appreciate your comment very much. I love the expression "flying cow"! It does seem appropriate.

Ann Carr from SW England on August 05, 2018:

Flying cow? Brilliant! I think these birds look like a prehistoric chicken but much prettier. You've gone into great detail here, Linda. I'd never heard of a hoatzin but it's a fascinating creature.

Great research and beautifully presented hub.

Ann

Linda Crampton (author) from British Columbia, Canada on August 02, 2018:

Thanks for the visit, Peggy. The claws are certainly helpful for the chicks. They are an interesting feature.

Peggy Woods from Houston, Texas on August 02, 2018:

This is certainly an interesting looking bird. I had never heard of a hoatzin or stinkbird so thanks for the education. The videos were good to watch. Those claws on the young birds' wings are really useful!

Linda Crampton (author) from British Columbia, Canada on July 29, 2018:

Hi, Heidi. Dealing with the smell could be interesting! I hope you have a good week.

Linda Crampton (author) from British Columbia, Canada on July 29, 2018:

Hi, Dora. I think the birds have interesting habits, too. They are certainly worth studying.

Heidi Thorne from Chicago Area on July 29, 2018:

Again, you have introduced us to another creature I had no idea existed. If they do, indeed, smell the way they do, we can understand why they're not featured in the zoo. :) But they do look beautiful!

Dora Weithers from The Caribbean on July 29, 2018:

Such an attractive creature with a name and characteristic that do not match its beauty. They do have interesting habits and survival skills. Thanks for the information.

Linda Crampton (author) from British Columbia, Canada on July 28, 2018:

Hi, Bede. I'd love to be surrounded by wild turkeys as you are. I think they would be interesting to observe and study.

Bede from Minnesota on July 28, 2018:

Thanks Linda for the introduction to this very interesting bird. I had never heard of it but some of its characteristics remind me somewhat of the wild turkeys that live all around me, such as its sociability, rareness of flight, and bizarreness. I like best the fact about the chicks jumping into the water below and climbing back up.

Linda Crampton (author) from British Columbia, Canada on July 28, 2018:

Thank you very much, Devika. I hope you have an enjoyable weekend.

Linda Crampton (author) from British Columbia, Canada on July 28, 2018:

I love birds, too, Pamela. The ability of the chicks to swim underwater is interesting. I hope researchers discover more about the hoatzin.

Devika Primić from Dubrovnik, Croatia on July 28, 2018:

A fascinating write up about such a different bird. You wrote with great interest and I enjoyed reading.

Linda Crampton (author) from British Columbia, Canada on July 28, 2018:

Hi, Bill. They are certainly unique birds! I appreciate your visit.

Linda Crampton (author) from British Columbia, Canada on July 28, 2018:

Hi, Genna. "Punk rock bird" is actually my favourite alternate name for the hoatzin! As far as I know, only humans are deterred by the bird's smell. Thank you for the comment.

Pamela Oglesby from Sunny Florida on July 28, 2018:

What a unique and pretty bird. I love all types of birds and find them so interesting. It is interesting that can swim under the water when threatened. I know some birds dive in the water for food, but this sounds different.

Bill De Giulio from Massachusetts on July 28, 2018:

Hi Linda. What an unique and interesting looking bird. I had never heard of the hoatzin? They are beautiful. Thank you for the education.

Genna East from Massachusetts, USA on July 28, 2018:

Bizarre is right. "Punk rock bird" is a perfect description for this poor little guy who at first glance is reminiscent of some kind of hangover from the Mesozoic Era, including the claw-bearing chicks. But what beautiful colors. At first glance, one wouldn't think that they are herbivores. Their helpers are endearing. Does their smell help dissuade predators or is it only humans that find it offensive? Very interesting article, Linda, and beautifully presented.

Linda Crampton (author) from British Columbia, Canada on July 27, 2018:

Hi, Flourish. I think the existence of helpers is a very interesting aspect of their life. Thank you for the comment. I hope you have a great weekend.

FlourishAnyway from USA on July 27, 2018:

What a beautiful and strange creature. I especially like that they have helpers in building nests and hatching young.

Linda Crampton (author) from British Columbia, Canada on July 27, 2018:

Hi, Manatita. I like the bird's colours, too. They often look lovely, especially when a bird has opened its wings.

manatita44 from london on July 27, 2018:

Very interesting bird and it has really nice colours. Looks like I may have seen it at home in Grenada. Not sure.

Linda Crampton (author) from British Columbia, Canada on July 27, 2018:

Thank you for the comment, Chitrangada. It is a unique bird. Nature is very interesting!

Chitrangada Sharan from New Delhi, India on July 27, 2018:

Thanks for introducing us to this unique bird!

As you mentioned above that they are found in northern part of South America, I don’t think I have ever seen or heard about this unique bird.

The detailed information you provide about these special birds is interesting and I enjoyed reading it.

Thanks for sharing the pictures of the bird and other details.

Linda Crampton (author) from British Columbia, Canada on July 27, 2018:

Hi, Mary. I think they are interesting birds, too. Their unusual characteristics are fascinating.

Mary Norton from Ontario, Canada on July 27, 2018:

This is the first time I've heard of hoatzins. They are really interesting especially in the care of their young. I would like to see one.

Linda Crampton (author) from British Columbia, Canada on July 27, 2018:

Thank you very much for the visit and the kind comment, Liz.

Liz Westwood from UK on July 27, 2018:

This is an incredibly informative article. I have learned a lot from it about the hoatzin.

Linda Crampton (author) from British Columbia, Canada on July 27, 2018:

Hi, Bill. "Prehistoric'" is a good word to describe the bird's appearance! Thanks for the comment.

Linda Crampton (author) from British Columbia, Canada on July 27, 2018:

Thanks, Eman. I appreciate your visit.

Linda Crampton (author) from British Columbia, Canada on July 27, 2018:

Hi, Jackie. Thanks for the visit. "Almost so ugly it is beautiful" is a great description of the bird! I've never heard of a baby bird being called a cub, either. The video is good, which is I why I included it, but I think there may have been a translation error when the creator was making their title.

Linda Crampton (author) from British Columbia, Canada on July 27, 2018:

Thank you very much, Viet. It's certainly a strange bird!

Bill Holland from Olympia, WA on July 27, 2018:

Facts I may not know? Start with the stinkbird itself. Never heard of it, never seen a picture of one. Thanks for the interesting article. It does look sort of prehistoric.

Eman Abdallah Kamel from Egypt on July 27, 2018:

It is a very informative article, Thank you.

Jackie Lynnley from the beautiful south on July 27, 2018:

Have never seen this bird before that I recall so thanks for all the great info on it. I have never heard of a bird's baby being called a cub. If I get to show off my new intelligence I will think of you!

It is almost so ugly it is beautiful, not so with that cub!

Viet Doan from Big Island, Hawaii on July 27, 2018:

I've never heard of this bird before! It looks like a cross between a pheasant, a vulture AND a turkey. And it stinks?!? That is really strange. Thank you, Linda, for a mesmerizing article. Now I want to go to South America to see the bird in person!