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The swifts are a family, Apodidae, of highly aerial birds. They are superficially similar to swallows, but are actually not closely related to passerine species at all; swifts are in the separate order Apodiformes, which they share with hummingbirds. The treeswifts are closely related to the true swifts, but form a separate family, the Hemiprocnidae.

The resemblances between swifts and swallows are due to convergent evolution, reflecting similar life styles based on catching insects in flight.

The family scientific name comes from the Ancient Greek απους, apous, meaning "without feet", since swifts have very short legs and never settle voluntarily on the ground, clinging instead to vertical surfaces. The tradition of depicting swifts without feet continued into the Middle Ages, as seen in the heraldic martlet.

Read more about Swift:  Description, Systematics and Evolution

Famous quotes containing the word swift:

    Ambition often puts Men upon doing the meanest offices; so climbing is performed in the same position with creeping.
    —Jonathan Swift (1667–1745)

    Where fierce indignation can no longer tear his heart.
    [Ubi saeva indignatio ulterius cor lacerare nequit.]
    —Jonathan Swift (1667–1745)

    Sad that our finest aspiration
    Our freshest dreams and meditations,
    In swift succession should decay,
    Like Autumn leaves that rot away.
    Alexander Pushkin (1799–1837)