Cypselomorphae is a clade of birds. It includes the living families and orders Caprimulgidae (nightjars, nighthawks and allies), Nyctibiidae (potoos), Apodiformes (swifts and hummingbirds), as well as the Aegotheliformes (owlet-nightjars) whose distinctness was only recently realized. The Apodiformes (which include the `Trochiliformes` of the Si.....