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. Several other families have recently been moved out of the Caprimulgiformes, being even more distantly related; it isn't clear whether these (oilbirds and frogmouths) should be included in the Cypselomorphae or no… (More on Cypselomorphae)