page_title: Flightless birds
section_title: Charadriiformes (Gulls, Terns, Auks)
hierarchical_section_title: Flightless birds / Examples of flightless birds / Charadriiformes (Gulls, Terns, Auks)
caption_attribution_description: English: Great Auks (extinct) in summer and winter plumage. Français&#160;: Un grand pingouin (espèce éteinte).
context_page_description: 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 60 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 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 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. The largest living flightless bird, is the Ostrich, although some extinct birds grew to larger sizes.
context_section_description: Great Auk (extinct)
caption: Great Auk
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