"possibly show paths this evolution may have taken. One of the biggest birds to have ever existed was the terror bird, which proliferated after dinosaurs vanished and stood up to 2.5 metres tall. By comparison, the ostrich, while not closely related, is the largest and heaviest living bird. It was probably the evasion of predators that drove most birds into the air, so their flightless cousins evolved because they had few enemies. Accordingly, such species are more likely to be found on islands, and Attenborough visits New Zealand to observe its great variety, most especially the kiwi. Also depicted is"
"Flightless bird Flightless birds are birds that through evolution lost the ability to fly. There are over 60 extant species including the well known ratites (ostrich, emu, cassowary, rhea and kiwi) and penguins. The smallest flightless bird is the Inaccessible Island rail (length 12.5 cm, weight 34.7 g). The largest (both heaviest and tallest) flightless bird, which is also the largest living bird, is the ostrich (2.7 m, 156 kg). Ostriches are farmed for their decorative feathers, meat and their skins, which are used to make leather. Many domesticated birds, such as the domestic chicken and domestic duck, have lost"
"also included here. Flightless bird Flightless birds are birds that through evolution lost the ability to fly. There are over 60 extant species including the well known ratites (ostrich, emu, cassowary, rhea and kiwi) and penguins. The smallest flightless bird is the Inaccessible Island rail (length 12.5 cm, weight 34.7 g). The largest (both heaviest and tallest) flightless bird, which is also the largest living bird, is the ostrich (2.7 m, 156 kg). Ostriches are farmed for their decorative feathers, meat and their skins, which are used to make leather. Many domesticated birds, such as the domestic chicken and domestic"
"is considered the limit for avian flight. The ""heaviest"" extant flying birds are known to weigh up to (there are several contenders, among which are the European great bustard and the African kori bustard). A mute swan, which may have personally lost the power of flight due to extreme weight, was found to have weighed . Meanwhile, the sarus crane is the tallest flying bird alive, at up to tall, standing about as high as ""Argentavis"" due to its long legs and neck. The largest known flying creatures overall are not birds, but instead the azhdarchid pterosaurs of the Cretaceous."
"first flightless paleognaths are known. Ostriches were present in Asia as recently as the Holocene, although the genus is thought to have originated in Africa. However, the ostrich order may have evolved in Eurasia. A recent study posits a Laurasian origin for the clade. The African ostrich is the largest living ratite. A large member of this species can be nearly tall, weigh as much as , and can outrun a horse. Of the living species, the Australian emu is next in height, reaching up to tall and about . Like the ostrich, it is a fast-running, powerful bird of"
"like a ratite's. It has unique characteristics quite unlike the sternum of any other bird (though vaguely convergent to that of the modern hoatzin), making it easily identifiable. Both ""P. antiqua"" and ""P. gigantea"" were clearly flightless, being large birds with far too short forelimbs and keels, the former in particular having highly reduced metacarpals, though ""P. wetmorei"" might have still been capable of limited flight. ""Paracrax gigantea"" in particular is a very large bird, reaching estimated heights of over , making it among the largest of bathornithids and among the tallest animals in its environment. Like most Cariamiformes, including"
"lineage. The Nicobar and spotted green pigeon were placed at the base of a lineage leading to the Raphinae, which indicates the flightless raphines had ancestors that were able to fly, were semi-terrestrial, and inhabited islands. This in turn supports the hypothesis that the ancestors of those birds reached the Mascarene islands by island hopping from South Asia. The lack of mammalian herbivores competing for resources on these islands allowed the solitaire and the dodo to attain very large sizes. The dodo lost the ability to fly owing to the lack of mammalian predators on Mauritius. Another large, flightless pigeon,"
"than an entire human arm. The species apparently had stout, strong legs and large feet which enabled it to walk with ease. The bill was large, rather slender, and had a hooked tip with a wide gape. ""Argentavis"" had an estimated wing span of (depending on the method used for scaling, i.e. regression analyses or comparisons with the California condor), a height of circa , and a mass of approximately . This made it the largest flying bird until another extinct species, ""Pelagornis sandersi"", was described in 2014 as having a larger size (although only weighing 22–40 kg). For comparison,"
"The non-flying penguins have wings adapted for use under water and use the same wing movements for swimming that most other birds use for flight. Most small flightless birds are native to small islands, and lead a lifestyle where flight would offer little advantage. Among living animals that fly, the wandering albatross has the greatest wingspan, up to ; the great bustard has the greatest weight, topping at . Most species of insects can fly as adults. Insect flight makes use of either of two basic aerodynamic models: creating a leading edge vortex, found in most insects, and using clap"
"the ability to fly for extended periods, although their ancestral species, the red junglefowl and mallard, respectively, are capable of extended flight. A few particularly bred birds, such as the Broad Breasted White turkey, have become totally flightless as a result of selective breeding; the birds were bred to grow massive breast meat that weighs too much for the bird's wings to support in flight. Flightlessness has evolved in many different birds independently. There were also other families of flightless birds, such as the now extinct Phorusrhacidae, that evolved to be powerful terrestrial predators. Taking this to a greater extreme,"
"more aerial than modern fowl, with a flight style more suited for gliding and soaring. Most of the galliform birds are more or less resident, but some of the smaller temperate species (such as quail) do migrate over considerable distances. Altitudinal migration is evidently quite common amongst montane species, and a few species of subtropical and subarctic regions must reach their watering and/or foraging areas through sustained flight. Species known to make extensive flights include the ptarmigans, sage-grouse (""Centrocercus""), crested partridge, green peafowl, crested argus, mountain peacock-pheasant (""Polyplectron inopinatum""), koklass pheasant (""Pucrasia macrolopha""), Reeves's pheasant and (""Syrmaticus reevesii""). Other species—most"
"Aegialornithidae is not quite clear. Various analyses place them sufficiently close to the Apodiformes to be included here, or into the unique owlet-nightjar lineage in the Cypselomorphae. ORDER APODIFORMES Apodiformes Traditionally, the bird order Apodiformes contained three living families: the swifts (Apodidae), the treeswifts (Hemiprocnidae), and the hummingbirds (Trochilidae). In the Sibley-Ahlquist taxonomy, this order is raised to a superorder Apodimorphae in which hummingbirds are separated as a new order, Trochiliformes. With nearly 450 species identified to date, they are the most diverse order of birds after the passerines. As their name (""footless"" in Greek) suggests, their legs are small"
"evidence. Seabirds fly low over water but gain altitude when crossing land, and the reverse pattern is seen in landbirds. However most bird migration is in the range of . Bird strike aviation records from the United States show most collisions occur below and almost none above . Bird migration is not limited to birds that can fly. Most species of penguin (Spheniscidae) migrate by swimming. These routes can cover over . Dusky grouse ""Dendragapus obscurus"" perform altitudinal migration mostly by walking. Emus ""Dromaius novaehollandiae"" in Australia have been observed to undertake long-distance movements on foot during droughts. While participating"
"Apodiformes Traditionally, the bird order Apodiformes contained three living families: the swifts (Apodidae), the treeswifts (Hemiprocnidae), and the hummingbirds (Trochilidae). In the Sibley-Ahlquist taxonomy, this order is raised to a superorder Apodimorphae in which hummingbirds are separated as a new order, Trochiliformes. With nearly 450 species identified to date, they are the most diverse order of birds after the passerines. As their name (""footless"" in Greek) suggests, their legs are small and have limited function aside from perching. The feet are covered with bare skin rather than the scales (scutes) that other birds have. Another shared characteristic is long wings"
"and other small creatures. They feed near the sea floor and no more than 200 metres offshore. The flightless cormorant is the largest extant member of its family, in length and weighing , and its wings are about one-third the size that would be required for a bird of its proportions to fly. The keel on the breastbone, where birds attach the large muscles needed for flight, is also greatly reduced. The flightless cormorants look slightly like a duck, except for their short, stubby wings. The upperparts are blackish and the underparts are brown. The long beak is hooked at"
"Flying squirrel Flying squirrels (scientifically known as Pteromyini or Petauristini) are a tribe of 50 species of squirrels in the family Sciuridae. They are not capable of flight in the same way as birds or bats but are able to glide from one tree to another with the aid of a patagium, a furry, parachute-like membrane that stretches from wrist to ankle. Their long tail provides stability in flight. Anatomically they are very similar to other squirrels but have a number of adaptations to suit their life style; their limb bones are longer and their hand, foot bones and distal"
"Thylacosmilidae from their kills. Unlike extant condors and vultures, the other species of teratorns generally had long, eagle-like beaks and are believed to have been active predators, being less ponderous than ""Argentavis"". When hunting actively, ""A. magnificens"" would probably have swooped from high above onto their prey, which they usually would have been able to grab, kill, and swallow without landing. Skull structure suggests that it ate most of its prey whole rather than tearing off pieces of flesh. Argentavis Argentavis magnificens was among the largest flying birds ever to exist, quite possibly surpassed in wingspan only by ""Pelagornis sandersi"","
"that it was sister taxa with ""Megavitiornis"", in a clade outside of the Galliformes crown group. ""Sylviornis"" was a huge flightless bird, long altogether, and weighing around on average. It is the most massive galliform known to have ever existed. It had a large skull with a high and laterally compressed beak surmounted by a bony knob. Its legs were rather short, but had strong toes with long nails. The skeleton has a number of peculiarities and differences that make ""Sylviornis"" stand apart from all other known birds: the clavicles were not fused to a furcula, the number of caudal"
"variously allied with Procellariiformes, Pelecaniformes and Anseriformes—and the largest flying birds of all time other than ""Argentavis"" were the huge ""Pelagornis"", ""Cyphornis"", ""Dasornis"", ""Gigantornis"" and ""Osteodontornis"". They had a wingspan of and stood about tall. Exact size estimates and judging which one was largest are not yet possible for these birds, as their bones were extremely thin-walled, light and fragile, and thus most are only known from very incomplete remains. The largest-known woodpecker is the possibly extinct imperial woodpecker (""Campephilus imperialis"") with a total length of about . The largest woodpecker confirmed to be extant is the great slaty woodpecker"
"Cassowary Cassowaries (), genus Casuarius, are ratites (flightless birds without a keel on their sternum bone) that are native to the tropical forests of New Guinea (Papua New Guinea and Indonesia), nearby islands, and northeastern Australia. There are three extant species. The most common of these, the southern cassowary, is the third-tallest and second-heaviest living bird, smaller only than the ostrich and emu. Cassowaries feed mainly on fruit, although all species are truly omnivorous and will take a range of other plant food, including shoots and grass seeds, in addition to fungi, invertebrates, and small vertebrates. Cassowaries are very shy,"
"to describe the typical walking style of the species. The huge adult male great bustard is possibly the heaviest living flying animal. It is also arguably the most sexual dimorphic extant bird species, in terms of the size difference between males and females. Going on mass, the only known bird with a higher dimorphism is the green peafowl (""Pavo muticus"") as the males are apparently near four times as heavy as the female. Among both bustards and all living birds, the upper reported mass of this species is rivaled by that of the kori bustard (""Ardeotis kori""), which, due to"
"around 20 kilograms. Other structural adaptations of flying animals include reduced and redistributed body weight, fusiform shape and powerful flight muscles; there may also be physiological adaptations. Active flight has independently evolved at least four times, in the insects, pterosaurs, birds, and bats. Insects were the first taxon to evolve flight, approximately 400 million years ago (mya), followed by pterosaurs approximately 220 mya, birds approximately 160 mya, then bats about 60 mya. Rather than active flight, some (semi-) arboreal animals reduce their rate of falling by gliding. Gliding is heavier-than-air flight without the use of thrust; the term ""volplaning"" also"
"Aiolornis Aiolornis incredibilis (syn ""Teratornis incredibilis""), of the teratorn family, was the largest known North American flight-capable bird, with a wingspan of up to approximately and a huge, deep, powerful bill. The typical body mass of this bird was estimated to be , significantly heavier than any extant flying bird. ""A. incredibilis"" presumably became extinct at the same time as the other megafauna in North America. It is sometimes called the giant condor because of its resemblance to the modern condors of California and South America, although it is bigger and in a different family. It is not well known"
"fly a great deal more than their close relatives, such as the brown eared pheasant (""C. mantchuricum"") and the blue eared pheasant (""C. auritum""). All three species are capable of hovering or volplaning over deep snow, with the aid of their great, wide tails. Eared pheasants move across deep snow by whirring their wings and fluttering close to the ground, and supporting their weight on their retrices. Eared pheasant flight was often described as poor by the hunter collectors of the 18th century, who used dogs to flush the birds from the ground for shooting. Eared pheasants do not waste"
"This specimen, which dates to the late Cretaceous period 66 million years ago, is indistinguishable from the femurs of modern seriemas, and belonged to a large bird about tall. Because of its age and geographic location, this unnamed species may have been close to the ancestry of both cariamids and phorusrhacids. Cariamiformes Cariamiformes (or Cariamae) is an order of primarily flightless birds that has existed for over 60 million years. The group includes the family Cariamidae (seriemas) and the extinct families Phorusrhacidae, Bathornithidae, Idiornithidae and Ameghinornithidae. Though traditionally considered as a suborder of Gruiformes, both morphological and genetic studies show"
"to Italy and was stranded with his companions who were turned to birds. The wandering albatross and the southern royal albatross are the largest of the albatrosses and are amongst the largest of flying birds. They have the largest wingspans of any bird, being up to from tip to tip, although the average is a little over . Large adult males of these two species may exceed in weight, as heavy as a large swan. The great albatrosses are predominantly white in plumage as adults, with birds becoming whiter as they age. The two royal albatrosses at all ages and"
"tallest North American bird, with a height of about 1.5 metres. Whooping crane have white colored bodies with black wing tips, face, and legs. The landscape of this natural park can be divided into four primary sections, each with its own unique geological features, wildlife habitats, and vegetation. Some of which include the Caribou, Birch Uplands, the Alberta plateau, Slave River Lowlands, and the Peace-Athabasca Delta. The Migratory Bird Treaty Act of 1918 was first passed in 1916, and sought to preserve migrating birds from extinction as a result of slaughter by suppliers to the milliner's trade, market hunters, and"
"are large passerine birds, amongst the largest in the order. They are ground living birds with strong legs and feet and short rounded wings. They are generally poor fliers and rarely take to the air except for periods of downhill gliding. The superb lyrebird is the larger of the two species. Females are 74–84 cm long, and the males are a larger 80–98 cm long—making them the third-largest passerine bird after the thick-billed raven and the common raven. Albert's lyrebird is slightly smaller at a maximum of 90 cm (male) and 84 cm (female) (around 30–35 inches) They have smaller,"
"sketch actually shows that the wings are not particularly short. They appear broad, as they commonly are in forest-adapted species, and the alula appears large, a feature of slow-flying birds. Its sternal keel was reduced, but not enough to prevent flight, as the adept flying ""Cyanoramphus"" parrots also have reduced keels, and even the flightless kakapo, with its vestigial keel, is capable of gliding. Furthermore, Hoffman's account states that it could fly, albeit with difficulty, and the first published illustration shows the bird on top of a tree, an improbable position for a flightless bird. The broad-billed parrot may have"
"name. There are no officially recognized subspecies, however, some authors believe there should be. The Karam or Kalam people of the New Guinea Highlands classify bats and flying birds as one group, yaket, and the dwarf cassowary, a very large, wingless, flightless bird as another, kobtiy. Yaket are bony with wings and fly in the air, while kobtiy are bony without wings and are terrestrial and of the forest. They distinguish kobtiy from other bony, wingless animals because kobtiy are not quadrupedal like dogs and lizards and are not limbless like snakes. (See Kalam languages.) John Gould first identified the"
"Moa Moa were nine species (in six genera) of flightless birds endemic to New Zealand. The two largest species, ""Dinornis robustus"" and ""Dinornis novaezelandiae"", reached about in height with neck outstretched, and weighed about . It is estimated that, when Polynesians settled New Zealand circa 1280, the moa population was about 58,000. Moa belong to the order Dinornithiformes, traditionally placed in the ratite group. However, their closest relatives have been found by genetic studies to be the flighted South American tinamous, once considered to be a sister group to ratites. The nine species of moa were the only wingless birds"
"more species of flightless birds (including the kiwi, several species of penguins, the takahe, the weka, the moa, and several other extinct species) than any other such location. One reason is that until the arrival of humans roughly a thousand years ago, there were no large land predators in New Zealand; the main predators of flightless birds were larger birds. Ratites belong to the superorder Palaeognathae birds, which include the volant tinamou, and are believed to have evolved flightlessness independently multiple times within their own group. Some birds evolved flightlessness in response to the absence of predators, for example on"
"another is that they functioned in parachuting, then gliding, then flight for originally arboreal insects. Pterosaurs were the next to evolve flight, approximately 228 million years ago. These reptiles were close relatives of the dinosaurs (and sometimes mistakenly considered dinosaurs by laymen), and reached enormous sizes, with some of the last forms being the largest flying animals ever to inhabit the Earth, having wingspans of over 9.1 m (30 ft). However, they spanned a large range of sizes, down to a 250 mm (10 in) wingspan in ""Nemicolopterus"". Birds have an extensive fossil record, along with many forms documenting both"