Taxonomy
Their relationship with other passerine groups is uncertain, but they seem closely related to some enigmatic African groups: the helmetshrikes (Prionops) and the shrike-flycatchers (Bias and Megabyas). They also appear to be close to some Asian groups: the woodshrikes (Tephrodornis), flycatcher-shrikes (Hemipus) and philentomas.
Though vangas were traditionally believed to be a small family of generally shrike-like birds, recent research suggests that several Madagascan taxa most similar in appearance and habits (and formerly considered to be) Old World warblers, Old World flycatchers or Old World babblers may be vangas. Yamagishi et al. found in 2001 that the newtonias appeared to belong with the vangas rather than the warblers and also that the Tylas was a vanga and not a bulbul. It also appears that Ward's Flycatcher and Crossley's Babbler belong with the vangas.
Read more about this topic: Vanga