Number of perching birds (order Passeriformes) that dart out to capture insects on the wing, particularly members of the Old World songbird family Muscicapidae and of the New World family Tyrannidae, which consists of the tyrant flycatchers. Many taxonomists expand the family Muscicapidae to include the thrushes, warblers, and babblers, treating the Old World flycatchers in two or more subfamilies, Muscicapinae (typical flycatchers) and Monarchinae (monarch flycatchers) and, in some classification systems, Rhipidurinae (fantailed flycatchers).