<P> The common swift (Apus apus) is a medium - sized bird, superficially similar to the barn swallow or house martin but somewhat larger, though not stemming from those passerine species, being in the order Apodiformes . The resemblances between the groups are due to convergent evolution, reflecting similar contextual development . The swifts' nearest relatives are thought to be the New World hummingbirds and the Southeast Asian treeswifts . </P> <P> Its scientific name Apus is Latin for a swift, thought by the ancients to be a type of swallow with no feet (from Ancient Greek α, a, "without", and πούς, pous, "foot"). </P> <P> Swifts have very short legs which they use primarily for clinging to vertical surfaces (hence the German name Mauersegler, literally meaning "wall - glider"). They never settle voluntarily on the ground, where they would be vulnerable to accidents and predation, and non-breeding individuals may spend up to ten months in continuous flight . </P> <P> The common swift was one of the many species described by the Swedish naturalist Carl Linnaeus in 1758 in the tenth edition of his Systema Naturae . He introduced the binomial name Hirundo apus . The current genus Apus was erected by the Italian naturalist Giovanni Antonio Scopoli in 1777 based on tautonymy . The word apus is the Latin word for a swift . It is derived from the Ancient Greek α, a, "without", and πούς, pous, "foot", based on the belief that these birds were a form of swallow that lacked feet . </P>

A bird that spend most of its lifetime in air
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