Flightless birds are birds which cannot fly. They rely on their ability to run or swim, and have evolved from their flying ancestors. There are about forty species living today, the best known being the ostrich, emu, cassowary, rhea, kiwi, and penguin.
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 a thousand years ago, there were no large land predators in New Zealand. The main predators of flightless birds were larger birds.
Some flightless varieties of island birds are closely related to flying varieties. This implies that flight is a significant biological cost. As soon as birds do not need to fly, there is selection against flight.
The smallest flightless bird is the Inaccessible Island Rail (length 12.5 cm, weight 34.7 g). The largest (both heaviest and tallest) living flightless bird, is the Ostrich (2.7 m, 156 kg), although some extinct birds grew to larger sizes.
Flightless birds are easy 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.
Examples of recent flightless birds[change | change source]
The following are flightless birds during or after the Holocene period.
Ratites[change | change source]
Anseriformes (Waterfowl)[change | change source]
- Dromornis (extinct)
Sphenisciformes (Penguins)[change | change source]
Charadriiformes (Gulls, Terns, Auks)[change | change source]
- Great Auk (extinct)
Psittaciformes (Parrots)[change | change source]
Columbiformes (Pigeons, Doves)[change | change source]
Other pages[change | change source]
Other websites[change | change source]
- TerraNature pages on New Zealand flightless birds
- Kiwi in Te Ara - the Encyclopedia of New Zealand
- Flightless birds in New Zealand
References[change | change source]
- "New Zealand Ecology - Moa". TerraNature. http://www.terranature.org/moa.htm. Retrieved 2007-08-27.
- "The Bird Site: Flightless Birds". http://www.nhm.org/birds/guide/pg019a.html. Retrieved 2007-08-27.
- "New Zealand's Icon:Flightless". http://www.savethekiwi.org.nz/AboutTheBird/NewZealandsIcon/KiwiCharacteristics/Flightless.htm. Retrieved 2007-08-27.
- Hunter, Laurie A (1988). "Status of the endemic Atitlan grebe of Guatemala: is it extinct?" (pdf). Condor 90 (4): pp. 906–912. doi:10.2307/1368847. http://elibrary.unm.edu/sora/Condor/files/issues/v090n04/p0906-p0912.pdf. Retrieved 2007-04-03.
- Taylor, Barry (1998). Rails: a guide to the rails, crakes, gallinules and coots of the world. Yale University Press. ISBN 0-300-07758-0.