The observed branch length heterogeneity suggests that ML methods might provide better estimates of avian phylogeny than MP, because parsimony equivalent models (i.e.WKH³QRFRPPRQPHFKDQLVP´ [NCM] model [79]) are unlikely to account effectively for branch length heterogeneity [80,81]. Indeed, it is clear that standard model selection approaches will indicate that WKH&)1YīPRGHOKDVDEHWWHUILW to the data than NCM [80], although we do note that there is debate regarding the question of whether MP should be viewed as a model [82]. Despite this prediction, our results are equivocal regarding the relative performance of these methods (e.g., compare Figure 3A to 3B). Indeed, the MP tree supports monophyly of Psittacopasserae and Austrodyptornithes (Figure 3B), unlike the ML tree, albeit with low (