fossils

The "giant chickens" of New Caledonia

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Vasika
Udurawane

Lead Writer
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Franz
Anthony

Editor and Artist
The strange extinct avian rulers of New Caledonia named Sylviornis, were among the oddest large birds ever to exist. For a long time we puzzled about what they were, only to find out that were indeed real “giant chickens”.

The island of New Caledonia once was home to a number of both ancient and strange birds, with one of them standing practically head and shoulders above the rest. This rather odd bird was the so-called New Caledonian giant fowl, Sylviornis neocaledoniae. The animal’s common name comes from the fact that it might have been a type of bird called a megapode, a distant relative of chickens and pheasants, a well-known group spread all over the globe. This whole family of birds is known as the Galliformes and  Sylviornis itself was a unique creature. Its subfossil remains were described by Francois Poplin in 1980. For a while the bird was incredibly hard to classify. At first it was thought to have been related to ostriches and emus. That is, until recently.


A new study by Trevor H. Worthy, Miyess Mitri, Atholl Anderson and colleagues allowed for a new conclusion. After an analysis of the 600 or so subfossil remains of the bird, some of which are more than 5000 years old, it was realized just what kind of bird Sylviornis was. It was not a real megapode as its name suggested, instead being a sort of primitive stem-Galliforme. Thus it lay at the very base of this huge bird family.


The reasoning behind its former classification as a megapode comes from supposed mounds that might have been made by these huge birds. After all, mound nests are a megapode trademark, so it might be reasonable to suggest that Sylviornis was building mounds too. Yet its new position in the family makes mound-building a highly unlikely act. Instead of building mounds, it was probably more adept at digging and scratching the ground in search of the roots, seeds and tubers that made up part of its diet along with the leaves of low-growing shrubs. It certainly had the foot anatomy for digging and rooting, according to the new study by Worthy. So while it was not a true “giant chicken,” Sylviornis was still part of Galliformes, so this is about as close as one will get.


Sylviornis is an example of what island life may do to most bird species. Not only was it very much bigger than any of its relatives but it was also flightless. It was a ground-dwelling herbivore that had a deep bill and a rather long neck and short, strong legs. Above its beak was a small crest that was probably used for display within the species. Avian evolution on islands has repeatedly created flightless giants, from the dodos of Mauritius to the moas of New Zealand and to Madagascar’s elephant birds. Sylviornis was 1.75 meters long, and weighed approximately 30 kg (66 lbs), making it the most massive of the gamebirds.


There are even clues to the birds’ extinction, and probably the extinction of many of the native New Caledonian fauna. Six years ago members of the same research team of Anderson and Worthy and a few other colleagues published a study about the end of these animals. It was published in the Journal of Pacific Archaeology, and included research material from New Caledonia’s Pindai Cave system. Pindai is one of the richest of the island’s fossil sites and contained the bones of about 45 species of birds. These included kagu, still alive today, species of snipe, owlet-nightjars and of course Sylviornis. Birds were not the only creatures here though. The animals found in Pindai include mice, rats, bats, monitor lizards and even the terrestrial crocodile Mekosuchus, the island’s apex predator. Radiocarbon dating of the fossils told the team that the chronologically youngest remains of the “giant chicken” were about 3000 years old.


The researchers also found out that Pindai contained charcoal remains, evidence of the island’s human settlers. This indicates that many of the native fauna survived well into the common era, living alongside the island’s first people, who were probably hunter-gatherers. One thing the team could not reveal though, was whether people were entirely to blame for Sylviornis’ extinction. The bird had certainly pulled through for a while before finally dying out so whether or not we caused its extinction or simply represented the final nail in the coffin is unknown.


Most of the large and extinct New Caledonian birds were megapodes as well. Many megapodes are still alive today in Australia especially, with famous examples including the Australian brushturkey and the malleefowl. Megapodes are known for building huge mound-shaped nests, and their young are somewhat precocial, being able to run around soon after hatching. Megapodes are also members of the larger gamebird group, the Galliformes which includes birds like pheasants, partridges and chickens. None of these birds are great fliers and instead spend their lives scratching the ground for their meals. Sometimes there is marked sexual dimorphism among gamebird species, taken to an extreme by the beautiful plumes of the peacock and several pheasants.

3986b46bb4f35aa1ff4d42167a12e0fc

Vasika
Udurawane

Lead Writer


http://sulc.us/6l0dv
http://www.eartharchives.org/articles/the-giant-chickens-of-new-caledonia/