Flightless birds
Flightless birds
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, rheaand 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.
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, rheaand 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 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, the terror birds (and their relatives the bathornithids), eogruids, geranoidids, gastornithiforms, and dromornithids (all extinct) all evolved similar body shapes – long legs, long necks and big heads – but none of them were closely related. Furthermore, they also share traits of being giant, flightless birds with vestigial wings, long legs, and long necks with some of the ratites, although they are not related.
Origin of flightless birds
Divergences and losses of flight within ratite lineage occurred right after the K-Pg extinction event wiped out all non-avian dinosaurs and large vertebrates 66 million years ago. The immediate evacuation of niches following the mass extinction provided opportunities for Palaeognathes to distribute and occupy novel environments. New ecological influences selectively pressured different taxon to converge on flightless modes of existence by altering them morphologically and behaviorally. The successful acquisition and protection of a claimed territory selected for large size and cursoriality in Tertiary ancestors of ratites. Temperate rainforests dried out throughout the Miocene and transformed into semiarid deserts causing habitats to be widely spread across the growingly disparate landmasses. Cursoriality was an economic means of traveling long distances to acquire food that was usually low lying vegetation, more easily accessed by walking. Traces of these events are reflected in ratite distribution throughout semiarid grasslands and deserts today.
Gigantism is not a requirement for flightlessness. The kiwi does not exhibit gigantism, along with tinamous, even though they coexisted with the moa and rhea that both exhibit gigantism. This could be the result of different ancestral flighted birds arrival or because of competitive exclusion.The first flightless bird to arrive in each environment utilized the large flightless herbivore or omnivore niche, forcing the later arrivals to remain smaller. In environments where flightless birds are not present, it is possible that after the K/T Boundary there were no niches for them to fill. They were pushed out by other herbivorous mammals.
New Zealand had 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
List of flightless birds
Many flightless birds are extinct; this list shows species that are either still extant, or became extinct in the Holocene (no more than 11,000 years ago). Extinct species are indicated with a dagger (†). A number of species that are suspected, but not confirmed to be flightless, are also included here.
Ratites
- Common ostrich strothio camelus
- Somali ostrich, Struthio molybdophanes
- Asian ostrich, Struthio asiaticus †
- Emus
- Emu, Dromaius novaehollandiae
- King Island emu, Dromaius novaehollandiae minor †
- Kangaroo Island emu, Dromaius baudinianus †
- Tasmanian emu, Dromaius novaehollandiae diemenensis †
- Emu, Dromaius novaehollandiae
- Cassowaries
- Dwarf cassowary, Casuarius bennetti
- Southern cassowary, Casuarius casuarius
- Northern cassowary, Casuarius unappendiculatus
- Moa (Dinornithiformes) †
- Elephant birds (Aepyornithiformes) †
- Kiwis
- Southern brown kiwi, Apteryx australis
- Great spotted kiwi, Apteryx haastii
- North Island brown kiwi, Apteryx mantelli
- Little spotted kiwi, Apteryx owenii
- Okarito kiwi, Apteryx rowi
- Rheas
- Greater rhea, Rhea americana
- Darwin's rhea, Rhea pennata
Anseriformes (waterfowl)
- Auckland Island teal, Anas aucklandica
- Campbell teal, Anas nesiotis
- Steamer ducks
- Fuegian steamer duck, Tachyeres pteneres
- Falkland steamer duck, Tachyeres brachypterus
- Chubut steamer duck, Tachyeres leucocephalus
- Amsterdam wigeon, Anas marecula †
- Bermuda flightless duck, Anas pachyscelus†
- Finsch's duck, Chenonetta finschi †
- New Zealand merganser, Mergus australis †
- Turtle-jawed moa-nalo, Chelychelynechen quassus †
- Small-billed moa-nalo, Ptaiochen pau †
- O'ahu moa-nalo, Thambetochen xanion †
- Maui Nui large-billed moa-nalo, Thambetochen chauliodous †
- Nฤnฤ-nui, Branta hylobadistes † (possibly flightless or very weak flier)
- Mihirung, Genyornis newtoni †
- California flightless sea-duck, Chendytes lawi †
- Kaua'i mole duck, Talpanas lippa †
- New Zealand geese, Cnemiornis †
Galliformes (game birds)
- New Caledonian giant scrubfowl, Sylviornis neocaledoniae †
- Noble megapode, Megavitornis altirostris †
- Viti Levu scrubfowl, Megapodius amissus †
Podicipediformes (grebes)
- Junin grebe, Podiceps taczanowskii
- Titicaca grebe, Rollandia microptera
- Atitlรกn grebe, Podilymbus gigas † (reportedly flightless)[21]
Pelecaniformes (pelicans, cormorants and allies)
- Flightless cormorant, Phalacrocorax harrisi
- Jamaican ibis, Xenicibis xymphithecus †
- Apteribis, A. glenos and A. brevis †
Sphenisciformes (penguins)
- King penguin, Aptenodytes patagonicus
- Emperor penguin, Aptenodytes forsteri
- Adรฉlie penguin, Pygoscelis adeliae
- Chinstrap penguin, Pygoscelis antarctica
- Gentoo penguin, Pygoscelis papua
- Little blue penguin, Eudyptula minor
- White-flippered penguin, Eudyptula minor albosignata
- Magellanic penguin, Spheniscus magellanicus
- Humboldt penguin, Spheniscus humboldti
- Galapagos penguin, Spheniscus mendiculus
- African penguin, Spheniscus demersus
- Yellow-eyed penguin, Megadyptes antipodes
- Waitaha penguin, Megadyptes waitaha †
- Fiordland penguin, Eudyptes pachyrhynchus
- Snares penguin, Eudyptes robustus
- Erect-crested penguin, Eudyptes sclateri
- Rockhopper penguin, Eudyptes chrysocome
- Royal penguin, Eudyptes schlegeli
- Macaroni penguin, Eudyptes chrysolophus
- Chatham penguin, Eudyptes sp. †
Coraciiformes (kingfishers, hornbills and allies)
- Saint Helena hoopoe, Upupa antaios †
Ciconiiformes
- Ascension night heron, Nycticorax olsoni †
Gruiformes (cranes, rails, and coots)
- Cuban flightless crane, Grus cubensis †
- Red rail, Aphanapteryx bonasia †
- Rodrigues rail, Erythromachus leguati †
- Woodford's rail, Nesoclopeus woodfordi(most likely flightless)
- Bar-winged rail, Nesoclopeus poecilopterus† (probably flightless)
- Weka, Gallirallus australis
- New Caledonian rail, Gallirallus lafresnayanus (likely †)
- Lord Howe woodhen, Gallirallus sylvestris
- Calayan rail, Gallirallus calayanensis
- Pink-legged rail, Gallirallus insignis
- Guam rail, Gallirallus owstoni
- Roviana rail, Gallirallus rovianae (flightless, or almost so)
- Tahiti rail, Gallirallus pacificus †
- Dieffenbach's rail, Gallirallus dieffenbachii †
- Chatham rail, Cabalus modestus †
- Wake Island rail, Gallirallus wakensis †
- Snoring rail, Aramidopsis plateni
- Inaccessible Island rail, Atlantisia rogersi
- Laysan rail, Porzana palmeri †
- Hawaiian rail, Porzana sandwichensis †
- Kosrae crake, Porzana monasa †
- Ascension crake, Mundia elpenor †
- Henderson crake, Porzana atra
- Invisible rail, Habroptila wallacii
- New Guinea flightless rail, Megacrex inepta
- Lord Howe swamphen, Porphyrio albus †
- North Island takahฤ, Porphyrio mantelli †
- Takahฤ, Porphyrio hochstetteri
- Samoan woodhen, Gallinula pacifica
- Makira woodhen, Gallinula silvestris
- Tristan moorhen, Gallinula nesiotis †
- Gough Island moorhen, Gallinula comeri
- Tasmanian native hen,Tribonyx mortierii
- Giant coot, Fulica gigantea (adults only; immature birds can fly)
- Hawkins' rail, Diaphorapteryx hawkinsi †
- Snipe-rail, Capellirallus karamu †
- Adzebills, Aptornis otidiformis and A. defossor †
Mesitorniformes (mesites)
- Brown mesite Mesitornis unicolor (possibly flightless, has not been seen flying)
Charadriiformes (gulls, terns, auks)
Great auk, Pinguinus impennis †
Falconiformes (birds of prey)
- Jamaican caracara, Caracara tellustris †
Psittaciformes (parrots)
- Kakapo, Strigops habroptilus
Columbiformes (pigeons, doves)
- Dodo, Raphus cucullatus †
- Rodrigues solitaire, Pezophaps solitaria †
- Viti Levu giant pigeon, Natunaornis gigoura†
- Saint Helena dove, Dysmoropelia dekarchiskos †
- Henderson ground dove, Gallicolumba leonpascoi †
Caprimulgiformes (nightjars)
- New Zealand owlet-nightjar, Aegotheles novaezealandiae †
Strigiformes (owls)
- Cuban giant owl, Ornimegalonyx spp. † (possibly flightless)
- Cretan owl, Athene cretensis † (probably flightless)
- Andros Island barn owl, Tyto pollens † (possibly flightless)
Passeriformes (perching birds)
- Lyall's wren, Xenicus lyalli †
- Long-billed wren, Dendroscansor decurvirostris †
- North Island stout-legged wren, Pachyplichas jagmi †
- South Island stout-legged wren, Pachyplichas yaldwyni †
- Long-legged bunting, Emberiza alcoveri †
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