The development of scientific consensus: Analyzing conflict and concordance among avian phylogenies

Recent developments in phylogenetic methods and data acquisition have allowed for the construction of large and comprehensive phylogenetic relationships. Published phylogenies represent an enormous resource that not only facilitates the resolution of questions related to comparative biology, but also provides a resource on which to gauge the development of concordance across the tree of life. From the Open Tree of Life, we gathered 290 avian phylogenies representing all major groups that have been published over the last few decades and analyzed how concordance and conflict develop among these trees through time. Nine large scale phylogenetic hypotheses (including a new synthetic tree from this study) were used for comparisons. We found that conflicts were over-represented both along the backbone (higher-level neoavian relationships) and within the oscine Passeriformes. Importantly, although we have made major strides in the resolution of major clades, recent published comprehensive trees, as well as trees of individual clades, continue to contribute significantly to the resolution of relationships throughout the avian phylogeny. Our analyses highlight the need for continued research into the resolution of avian relationships.