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Series 10
Big birds
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T
here was a time when big birds ruled the Earth. These flightless descendants of dinosaurs had speed and agility, strong necks and strong beaks to crush their prey. As time moved on these large predatory birds were replaced in the food chain by mammals but some big birds still exist today. Our modern-day big birds are not hunters like their ancestors, feeding instead on leaves and berries, but they have retained much of their strength, speed and size.
What is a bird? Like mammals, birds are warm-bloooded vertebrates (animals with a backbone). However, birds are distinguished by unique characteristics that make them the most accomplished of all flying animals. Scientists have come to believe birds are living dinosaurs, having evolved from avian dinosaurswhich,unliketheir non-aviancounterparts, were never wiped out. For this reason birds have developed very differently from other animals. They have wings, beaks, feathers, hollow bones and a highly efficient respiratory system. They also produce their young in eggs, which are usually laid in a protective nest and nurtured until they are mature enough to hatch. Birds vary greatly in size, from the tiny hummingbird, which weighs less than 30g, to the giant ostrich, which weighs up to 160kg (see Ostrich), but even the ostrich would be outsized by the big birds of earlier times.
An emu chick hatching
Ratites The ratites are large, flightless birds that have no ridge on their sternum. It is to this ridge that wing muscles are attached in birds that can fly. It is thought ratites evolved from flying ancestors whose breast muscles and wings degenerated as they increased in size and weight and improved their ability to run from danger. Living examples of ratites are the African ostrich and the Australian emu.
Largest living bird Ostrich Struthio camelus The ostrich is the largest living bird, growing up to 2.8m tall and weighing in at up to 160kg. Although it is flightless (see Ratites), the ostrich is known for its speed, running up to 70km/h for as long as 30 minutes. The ostrich lives on the deserts and plains of Africa, however it is farmed in many parts of the world for its meat, leather and feathers. Its usual diet is plants but the ostrich will sometimes eat lizards and turtles when they are found. Along with a featherless neck and legs, an ostrich has long, thick eyelashes, which are almost 5cm in diameter, to help protect its eyes from sand. A running ostrich
A recreation of a moa pictured with two Maori hunters, circa 1906
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Over the last few decades, we’ve slowly come to the amazing realisation that birds not only evolved from the dinosaurs but in fact birds are dinosaurs Dr Karl Kruszelnicki in Dinosaurs Aren’t Dead
Australian big birds
Prehistoric birds
Terror birds
Dromornithids
The terror bird was flightless but highly predatory. Standing almost 3m tall and weighing 360kg, this giant roamed South America from 27 million years ago until about 5000 years ago. Its beak was shaped much like an eagle’s and was ideal for tearing meat. It’s believed it was an ambush predator, pouncing out at its prey from a hiding place. Its great weight would have made long chasesdifficult, unlike today’s ostrich.
Emu Dromaius novaehollandiae
Phorusrhacos, Brontornis
Also known as mihirung, these were Australia’s prehistoric birds. Up to 3m tall and 500kg in weight, the mihirung lived in the early Eocene Epoch, 50 million years ago. Their structure was similar to that of an emu and included powerful legs, reduced wing sizeandno ridgeonthe sternum.Despitethese sharedcharacteristics,scientistsbelievethey are not closely related to emus or cassowaries but are more likely to be related to waterfowl. For all the mihirung’s size, it is believed they were herbivores as they had no hook on the end of their beak and no talons for grasping prey. Mihirungs had hollow bones but were flightless.
Our largest native bird is the emu, which grows up to 1.9m tall and can weigh almost 60kg. The emu lives in flocks with dozens of birds and feeds on seeds, berries, grasses and leaves. It has also been known to eat insects including grasshoppers and caterpillars. Found all across Australia, the emu is generally regarded as a friendly local bird, however in areas of cereal farming it can be regarded as a serious pest. A male emu caring for his two chicks. The male incubates the eggs and raises the chicks.
Cassowary Casuarius casuarius
Phorusrhacos, the terror bird
Big birds in mythology
Extinct birds
Thunderbird In the mythology of the North American Indian, the thunderbird is a powerful spirit intheformofabirdandsaidtocausestorms intheformofabirdandsaidtocaus estorms as it flies. Lightning was believed to flash from its beak and eyes and the beating of its wings was thought to arouse thunder. It is depicted as large and colourful, with horns on its head and teeth in its beak.
Elephant bird Aepyornis The elephant bird was a giant species native to Madagascar that became extinct about the 1600s. These flightless birds are thought to have resembled monstrous ostriches, with the largest reaching heights of up to 3m and weighing as much as 455kg. Their eggs are the largest single cells in the animal kingdom and can hold up to eight litres of liquid. The largest of the elephant birds, aepyornis maximus, was also the heaviest of all known birds. Scientists believe habitat destruction was a likely cause of its extinction.
Roc The elephant bird
Chicken Emu
A Gustave Dore illustration of Sinbad the sailor encountering a roc chick hatching, from the book One Thousand And One Nights
Cassowary
Moa Dinornis This large flightless bird inhabited the grasslands and forests of New Zealand until the 1700s. It was a herbivore and its great height of up to 3m allowed it to source its food from higher in the trees than other grazing animalscould reach. The female was 1.5 times larger and almost three times heavier than the male. Scientistsbelieve the moa’s neck probably projected forwards, like a kiwi, rather than upwards as usuallydepicted. It was hunted to extinction by native Maoritribesmen before Europeans arrived.
Size comparison
Ostrich
Elephant bird
3m Moa Ostrich Moa
A thunderbird depicted on a Native American totem pole
The roc is an enormous legendary bird of prey popularised by stories told by Marco Polo and in the tale of Sinbad the sailor. Often said to be white and shaped like an eagle, the roc was thought to have been able to carry off and eat elephants. Scientists say the origin of the myth may lie in embellishments of the eagle’s ability to carry away a newborn lamb as its prey. The legend is known to both Eastern and Western traditions.
2m
Phorusrhacos
The second largest bird in Australia is the cassowary, which grows up to 1.7m tall and weighs up to 70kg. The cassowary lives in the rainforests of Northern Queensland and has a diet of fallen fruit but has been known to eat small invertebrates. These flightless,brightlycoloured birds have a protective casque, or horny growth, on their head and neck wattles that can change colour according to the bird’s mood. Cassowaries can pose a threat to humans because of their powerful legs and sharp claws. The adults are solitary when notbreeding.
A cassowary. Classified as endangered, it is restrictedtorainforests in North Queensland
Wandering albatross
Did you know? n The popular notion that an ostrich hides its head in the sand when frightened is a myth. It stems from the fact that when threatened an ostrich will sometimes lay its body on the ground and use rocks to hide its head. To a distant observer this may look like the ostrich has its head in the ground. n Emus are extremely inquisitive and easily attracted by strange behaviour or movements. This is why they seem so friendly when they encounter humans at animal parks. n The wandering albatross, native to Australia, has the largest wingspan of any bird. It can measure up to 3.5m. n The study of birds is called ornithology. This derives from the Greek words ornithos, meaning bird, and logos, meaning knowledge. n In 2006 a school student discovered bones of a bird that were 15 million years old in the Patagonia region of Argentina. The skull was almost one metre long. n The Yuwaalaraay people and otherAboriginal groups in NSW believe the sun was made by throwing an emu’s egg into the sky. n The ostrich only has two toes on each foot and can live up to 70 years. n The male emu cares for eggs during incubation and for up to eight months after hatching. Emus have been extinct in Tasmania since 1850. n Measuring up to one metre long, the wedgetailed eagle is Australia’s largest living bird of prey and one of the largest eagles in the world.
Wedge-tailedeagle
Sources and further study n Animal,The Definitive Visual Guide, by David Burnie,
Dorling Kindersley (DK) Limited , Tim Haines, BBC n Riversleigh, The Story Of Animals In Ancient Rainforests Of Inland Australia , by Michael Archer, Suzanne Hand, Henk Godthelp, Reed Books n The World Book Encyclopedia, World Book Inc ncyclopedia Britannica, Encyclopedia Britannica Inc n E ncyclopedia n Dinosaurs Aren’t Dead, The Shocking Story Of Dinosaur Evolution, by Dr Karl Kruszelnicki, PanMacmillanAustralia n Australian Beasts, ABC Science, abc.net.au/science/ausbeasts/ n Five Of The Largest Birds In History, Scienceray, scienceray.com/biology/zoology/five-of-thelargest-birds-in-history/ n Animals,NationalGeographic,animals. nationalgeographic.com/animals/ ?source=NavAniHome n Magnificent Mihirungs: The Colossal Flightless Birds Of The Australian Dreamtime , by Peter F. Murray and PatriciaVickers-Rich,IndianaUniversityPress Nationa l n MythicalCreaturesexhibition,AustralianNational Maritime Museum,Darling Harbour n Walking With The Beasts, A Prehistoric Safari
1m Elephant bird
Egg sizes
C as sowa ry
Em u
Adult human
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[email protected] [email protected]: Phone: 9288 9288 2542 Editor: Troy Editor: Troy Lennon Words: Dannielle Words: Dannielle Elms Graphics: Paul Graphics: Paul Leigh and Will Pearce
