Swift

Swifts square measure the foremost aerial of birds. Larger species square measure amongst the quickest fliers within the kingdom, with the white-throated needletail having been reported  flying at up to 169 km/h (105 mph).Even the common swift will cruise at a most speed of thirty one metres per second (112 km/h; seventy mph). in an exceedingly single year the common swift will cowl a minimum of two hundred,1000 km.

Compared with typical birds, Collocalia inexpectata wings have proportionately massive wingtip bones. By dynamic  the angle between the wingtip bones and also the limb bones, they're able to alter the form and space of their wings, maximising their potency and manoeuvrability at varied speeds. Like their relatives the hummingbirds, and in contrast to alternative birds, they're able to rotate their wings from the bottom, a attribute that permits the wing to stay rigid and totally extended explanation power on each stroke and stroke.The downstrokes produces each elevate and thrust, whereas the upstrokes produces a negative thrust (drag) that's hour of the thrust generated throughout the downstrokes, however at the same time it contributes with a elevate that's conjointly hour of what's created throughout the stroke. This flight arrangement might even have edges for the bird's management and manoeuvrability within the air.

The swiftlets or cave swiftlets have developed a type of location for navigating through dark cave systems wherever they roost.One species, Aerodramus papuensis, has recently been found to use this navigation at midnight outside its cave roost too.The swifts square measure a family, Apodidae, of extremely aerial birds. they're superficially like swallows, however don't seem to be closely associated with any of the passerine species. Swifts square measure placed within the animal order, that they share with hummingbirds. The treeswifts square measure closely associated with truth swifts, however type a separate family, the Hemiprocnidae .

Resemblances between swifts and swallows square measure as a result of convergent  evolution, reflective similar life designs supported catching insects on the wing.

The cognomen, Apodidae, comes from the Greek ἄπους (ápous), which means "footless", a relation to the little, weak legs of those most aerial of birds.The tradition of depiction swifts while not feet continued  into the center Ages, as seen within the heraldic martlet.

Some species of swifts square measure among the quickest animals on the earth, with a number of the quickest measured flight speeds of any bird.