Cypselomorphae

Strisores ( ), sometimes called nightbirds, is a clade of birds that includes the living families and orders Caprimulgidae (nightjars, nighthawks and allies), Nyctibiidae (potoos), Steatornithidae (oilbirds), Podargidae (frogmouths), 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 Sibley–Ahlquist taxonomy) and the Aegotheliformes form the Daedalornithes.

==Description== The material evidence for this group is very equivocal; the most ancient Strisores are quite nondescript tree-dwellers but already tend towards peculiarly apomorphic feet, and no Cretaceous fossils are known. Torpor and other metabolic peculiarities are frequently found in this group, perhaps more often than in any other bird lineage. The synapomorphies that define this clade are the ossa maxillaria separated by a large cleft, a mandible with short pars symphysialis, and rami mandibulae slender in their distal half.