A pruned version of the BirdTree Stage 2 maximum clade credibility tree
(Hackett backbone), containing ~660 species from the Corvoidea and
allied passerine families. Deliberately smaller than avonet_subset
(~920 species) so that reconciliation produces unresolved species
suitable for reconcile_augment(). Tip labels use underscores.
Source
Jetz et al. (2012) The global diversity of birds in space and time. Nature 491:444–448. doi:10.1038/nature11631