Flightless birds

Flightless birds are birds that through evolution have lost the ability to fly. There are over 60 extant species, including the well known ratites (ostriches, emu, cassowaries, rheas 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).

Evolution

While the loss of flight might seem to be a disadvantage, a number of species have managed to use this to their advantage. Flight requires a lot of energy and also certain body characteristics that might be a disadvantage on the ground. For example, a bird that lives on the ground and needs to run quickly from predators might be better off without large wings.

Types of Flightless Birds

There are many different types of flightless birds:

• Ratites: These are large, flightless birds with a flat breastbone rather than a keeled one such as the ostrich, emu, and kiwi. They cannot fly because they lack the keel to which flight muscles attach in flying birds.

• Penguins: Penguins are a group of flightless birds that live almost exclusively in the Southern Hemisphere, especially in Antarctica. They are adapted for life in the water and have flippers instead of wings.

• Dodo: The dodo was a flightless bird that was endemic to the island of Mauritius. It went extinct by the late 17th century due to habitat loss and hunting.

• Kakapo: The kakapo is a species of large, flightless, nocturnal, ground-dwelling parrot of the super-family Strigopoidea, endemic to New Zealand.

Conservation

Many flightless birds are extinct (e.g. the dodo), and many are endangered. Humans have had a hand in this, as they have brought predators to islands that were previously free of them, hunted the birds, and destroyed their habitats.

See also

• List of flightless birds
• Bird flight
• Evolution of birds

References

Flightless birds Resources
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