'Flightless birds' are birds which lack the ability to fly, relying instead on their ability to run, and are thought to have evolved from their flying ancestors.
[1] There are about forty species in existence today,
[ The Bird Site: Flightless Birds ] the best known being the
ostrich,
emu,
cassowary,
rhea,
kiwi, and
penguins. It is believed by some that most flightless
birds evolved in the absence of predators, on islands, and lost the power of flight because they had few enemies — although this is likely not the case for the
ratites; the
ostrich,
emu and
cassowary, as all have claws on their feet/wings to use as a weapon against predators.
Two key differences between flying and flightless birds are the smaller wing bones of flightless birds and the absent (or greatly reduced) keel on their breastbone. The keel anchors muscles needed for wing movement.
Flightless birds also have more feathers than flying birds.
New Zealand has more species of flightless birds (including the
kiwis, several species of
penguins, and the
takahe) than any other country. One reason is that until the arrival of humans roughly 1000 years ago, there were no large land predators in New Zealand; the main predators of flightless birds were larger birds.
[2]
Some flightless varieties of island birds are closely related to flying varieties, implying flight is a significant biological cost.
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) (although some extinct species grew to larger sizes).
Flightless birds are the easiest to take care of in captivity because they do not have to be caged. Ostriches were once farmed for their decorative feathers. Today they are raised for meat and for their skins, which are used to make leather.
There were also other families of flightless birds, such as the now extinct
Phorusrhacidae, that evolved to be very powerful terrestrial predators.
==List of
recent flightless birds
==
Ratites
★
Ostrich
★
Emu
★
Kangaroo Island Emu (extinct)
★
King Island Emu (extinct)
★
Cassowaries
★
Moa (extinct)
★
Elephant birds (extinct)
★
Kiwis
★
Rheas
Grebes
★
Junin Flightless Grebe
★
Titicaca Flightless Grebe
★
Atitlán Grebe (extinct, reportedly flightless [Hunter 1988])
Pelican-like birds
★
Flightless Cormorant
Petrel-like birds
★
Penguins
Kingfishers and relatives
★
Giant Hoopoe (extinct)
Duck-like birds
★
Moa-nalos (extinct)
★
Magellanic Flightless Steamer Duck
★
Falkland Flightless Steamer Duck
★
White-headed Flightless Steamer Duck
★
Auckland Island Teal
★
Campbell Island Teal
Rails and relatives
★
Red Rail (extinct)
★
Rodrigues Rail (extinct)
★
Woodford's Rail (probably flightless)
★
Bar-winged Rail (extinct, probably flightless)
★
Weka
★
New Caledonian Rail
★
Lord Howe Woodhen
★
Calayan Rail
★
New Britain Rail
★
Guam Rail
★
Roviana Rail ("flightless, or nearly so" [Taylor 1998])
★
Tahiti Rail (extinct)
★
Dieffenbach's Rail (extinct)
★
Chatham Rail (extinct)
★
Wake Island Rail (extinct)
★
Snoring Rail
★
Inaccessible Island Rail
★
Laysan Rail (extinct)
★
Hawaiian Rail (extinct)
★
Kosrae Island Crake (extinct)
★
Henderson Island Crake
★
Invisible Rail
★
New Guinea Flightless Rail
★
Lord Howe Swamphen (extinct, probably flightless)
★
North Island Takahe (extinct)
★
Takahe
★
Samoan Wood Rail
★
Makira Wood Rail
★
Tristan Moorhen (extinct)
★
Gough Island Moorhen
★
Adzebills (extinct)
★
Kagu
★
Tasmanian Native-hen
Gulls and relatives
★
Great Auk (extinct)
===
Parrots===
★
Kakapo
★
Broad-billed Parrot (extinct)
Doves and relatives
★
Dodo (extinct)
★
Rodrigues Solitaire (extinct)
★
Viti Levu Giant Pigeon (extinct)
Owlet-nightjars
★
New Zealand Owlet-nightjar (extinct)
Songbirds
★
Stephens Island Wren (extinct)
See also
★
Ratite
★
Extinct birds
★
Gastornis
★
Phorusrhacidae
★
Dinosaurs
★
★
Feathered dinosaurs
★
★
Origin of birds: Are some dinosaurs secondarily flightless?
References
★
Status of the Endemic Atitlan Grebe of Guatemala: Is it Extinct?, , Laurie A, Hunter, Condor,
★
Rails: A Guide to the Rails, Crakes, Gallinules and Coots of the World, , Barry, Taylor, Yale University Press, 1998, ISBN 0-300-07758-0
1. TerraNature
2. New Zealand's Icon:Flightless
External links
★
TerraNature pages on New Zealand flightless birds