The swifts are a family, Apodidae, of highly aerial birds. They are superficially similar to swallows but are not closely related to them. Swifts are the most aerial of birds.
Swifts have a worldwide distribution in arctic and temperate areas, but like swallows and martins, the swifts of temperate regions are strongly migratory and winter in the tropics. Some species can survive short periods of cold weather by entering torpor, a state similar to hibernation.