Having no enemies, and taking its food primarily through diving along the food-rich shorelines, the bird eventually became flightless.
Ratites, all of whom are flightless, lack a strong keel.
Some flightless varieties of island birds are closely related to flying varieties, implying flight is a significant biological cost.
A dragon starts as a flightless "hatchling", in an epic quest they grow up to an "adult dragon" able to fly.
Being flightless makes recolonisation of burnt areas more difficult for these beetles.
In flightless birds, however, its shape may be slightly different, or it might be absent entirely.
Bristle-thighed curlews are unique among shorebirds in that they are flightless during molt.
Originally thought to be one of the earliest members of flightless birds, alvarezsaurids have recently been regarded as more basal theropods.
