Members of the family Apodidae are known as swifts. They are superficially similar to swallows, but are not closely related to passerine birds. Swifts are the most aerial of birds having robust bodies, short and stiff tails, longer and straighter wings. Their plumage is compact and is predominantly black, gray or brown. Larger species are amongst the fastest fliers in the animal kingdom. All swifts eat insects. When at rest, they cling to vertical surfaces using their sharp claws and stiff tails.
Like their relatives the hummingbirds, and unlike other birds, they are able to rotate their wings from the base, a trait that allows the wing to remain rigid and fully extended deriving power on both upstroke and downstroke. Swift identification is challenging as plumage colors change in tone as it gets worn and soiled. Additionally, swifts fly fast and high where field marks can be difficult see with precision. There are six genera and 13 species of swifts known to occur in Peru. Photo: Pale-rumped Swift, Photo: Rich Hoyer.