The Swifts (Apodidae) are a family of 102 species of highly aerial birds. They are superficially similar to swallows but are actually not closely related to passerine species at all; swifts are in fact closely raleted to hummingbirds.
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 - apous - meaning "without feet", since swifts have very short legs and never settle voluntarily on the ground, perching instead on vertical surfaces.
Swifts are the most aerial of birds. Larger species, such as White-throated Needletail, are amongst the fastest fliers of all animals. Even the Common Swift cruises at 18–50 km/h and is capable of 216 km/h for short bursts. In a single year the common swift can cover at least 200,000 km.