By Kate, CC BY-SA 2.0  Etymology: Wearing the Hair Long Behind First Described By: Illiger, 1811 C… | Abby's Pins


By Kate, CC BY-SA 2.0  Etymology: Wearing the Hair Long Behind First Described By: Illiger, 1811 C…

By Kate, CC BY-SA 2.0  Etymology: Wearing the Hair Long Behind First Described By: Illiger, 1811 Classification: Dinosauromorpha, Dinosauriformes, Dracohors, Dinosauria, Saurischia, Eusaurischia, Theropoda, Neotheropoda, Averostra, Tetanurae, Orionides, Avetheropoda, Coelurosauria, Tyrannoraptora, Maniraptoromorpha, Maniraptoriformes, Maniraptora, Pennaraptora, Paraves, Eumaniraptora, Averaptora, Avialae, Euavialae, Avebrevicauda, Pygostaylia, Ornithothoraces, Euornithes, Ornithuromorpha, Ornithurae, Neornithes, Neognathae, Neoaves, Inopinaves, Opisthocomiformes, Opisthocomidae Status: Extant, Least Concern Time and Place: Within the last 10,000 years, in the Holocene of the Quaternary  Hoatzin are known from the Amazon Basin Physical Description: Hoatzin are weird birds, in terms of literally everything – proportion, physical traits, everything. They are the size of your typical pheasant, about 62 to 70 centimeters long, and are literally unmistakeable to spot. With small heads, long necks, and huge round bodies, they look almost like nonavian dinosaurs in terms of overall body shape. The small head features a tiny pointed beak, blue patches around a red eye, and a noticeable crest of orange to brown feathers all around the back of the head like a crown. The back of its neck is black and white spotted, with the throat a more beige-yellow color. This transitions to red feathers along the belly and rump. The back of the hoatzin is brown, while the wings are brown, red, and black and white striped like the back of the neck. The legs are stout and grey. The tail feathers are black with white tips. The females have shorter crests than males, but otherwise look the same – and the juveniles look similar to the adults. The babies are brown and fluffy, with very reduced wings and – often noticed – external wing claws, though these arent unique to the Hoatzin and are found on other living dinosaurs (birds).  By Adlaya The internal anatomy of the Hoatzin is notable, too – it has a very large crop that fermates vegetable matter like mammalian ruminants, a structure that isnt found in any other known dinosaur (not to say this might not have evolved in extinct forms; we just dont have fossil evidence for it). This fermentation gives the Hoatzin a very smelly odor as it digests its food!  By Francesco Veronesi, CC BY-SA 2.0  Diet: The Hoatzin feeds primarily on leaves and fruit, including green leaves and buds. Fruit are the primary food for the Hoatzin during the dry season. It is an obligate herbivore. Behavior: The Hoatzin feeds mainly in large social groups in the early morning and near dusk, and also during moonlit nights. It will balance itself on branches using the bump of its crop, and it climbs clumsily amongst the branches – they are even fairly tame, though they get stressed out by frequent human visits, but its easy to approach in the wild. It makes a variety of calls, including hisses, grunting, squawking, and croaking, usually made in conjunction with raising and lowering their wings. While mostly tame, they can get very defensive of their nests. They are very bad fliers, cannot swim, walk, or even hop – they move from branch to branch clumsily and never go back down to the ground. They make short migrations of up to 2 kilometers to find fresh food, but nothing more.   By Warren H., CC BY 2.0  The Hoatzin makes its nests in the rainy season, depending on where it lives – so any time of the year, really, since the rainy season varies from place to place in its range. They form monogamous mated pairs, and enlist the help of up to six helpers – usually their former children – in preparing their nests and caring for the new young. These nests are placed in dense trees, usually over water surfaces, and are made out of unlined platforms of dry sticks. Usually the nests are placed all close together, with up to 250 nests placed along stretches of trees for up to 7 kilometers. Usually two eggs are laid which are incubated by the whole family. The chicks have dark brown, fluffy coats, and can escape predators by diving into the water and swimming away before climbing back into the trees. They leave the nest at two to three weeks old, and cant fly for a little while longer – instead, they depend on the adults of their families for food for another three months. The more children there are from past breeding seasons, the less the mother works; the father works the same amount no matter what. They finally leave the family to breed on their own at two to three years of age. 
By Brian Ralphs, CC BY 2.0 Ecosystem: Hoatzin live in tropical wet forests, usually alongside rivers and lakes – where the wettest vegetation can be found, as they rarely drink, and instead get most of their water from their leaves and fruit. They are often found in mangrove habitats as well for those populations near the coast. They are forced out of these habitats when their homes dry out, but they avoid moving if they can help it. By Cláudio Dias Timm, CC BY-SA 2.0  Other: Despite being extremely noticeable birds, Hoatzin are not endangered – probably because no one wants to hunt them with all the stinkiness (and associated bad taste)! Still, ecotourism does stress out the birds and leads to lower survival rates of chicks, and they are heavily threatened by planned work in the Amazon basin – which is why we have to protect these habitats. Hoatzin are extremely unique birds – unlike any others, and in their own phylogenetic grouping. In fact, for the longest time we had no clue what they were closely related to. For now, it seems theyre just outside the group Telluraves – the group of most tree-dwelling birds such as birds of prey, trogons, kingfishers, woodpeckers, parrots, and passerines. But even that is up to debate, and more research is needed before we can be sure. ~ By Meig Dickson Sources under the Cut  Jobling, J. A. 2010. The Helm Dictionary of Scientific Bird Names. Christopher Helm Publishing, A&C Black Publishers Ltd, London. Prum, R.O. et al. (2015) A comprehensive phylogeny of birds (Aves) using targeted next-generation DNA sequencing. Nature 526, 569–573. 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.









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